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Snow Crystals Vol. #18 3/5/12


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Snow Crystals Vol. #18 March 5, 2012


Editors notes by Peter Wolf
Blockbuster Winter For Bentley
by Wayne Howe

Blair Williams and Wilson Bentley
by  Duncan C. Blanchard
Bentley’s Most Singular Observation
by Jon Nelson

Editors notes by Peter Wolf

As I look out this early March day onto bare ground with just a scattering of snow about Jericho, following one of the snowiest winters of 2011, I can only marvel at the dynamic nature of the weather. I think that is one of the things that captivated Wilson Bentley throughout his life and sparked his studies in various weather phenomena including snow, rain and all forms of precipitation in between, as well as aurora borealis, frost, dew and clouds. During his life he wrote over 60 articles on these various phenomena and although he did not receive substantial recognition at the time we must say that the interest in Snowflake Bentley and his work still flourishes

This Newsletter brings some of that recognition to the forefront with Wayne Howe, The Jericho Historical Society's Archivast and new National star, after his appearance on CBS Evening News (link to video). Wayne talks of this and the other recent press including the article in American Profile linked here and The Burlington Free Press. We supplied photos and archived material for all these stories. We also have an article from Duncan Blachard on his connection to Bentley & Jericho through Blair Williams. Jon Nelson tells us of Bentley’s Most Singular Observation on crystal formation.

Blockbuster Winter For Bentley by Wayne Howe

This winter the story of Wilson Bentley  was seen by millions of Americans. Back in Jericho activity at the  Historical Society website reached their highest levels as folks clicked to fine out more about the Snowflake Man.

A feature piece at the end of the CBS Evening News ran almost three minutes. The well edited piece featured Bentley's beautiful snowflake photographs along with the famous Pathe news video of Bentley at work. Luckily, Jericho was dressed up with the slightest bit of snow when the friendly film crew arrived. Video of a horse drawn sleigh flying over the snow and Bentley's frosty grave site in Jericho Center set a nice tone. As the Historical Socieity's archivist  I was interviewed inside the Red Mill by the large roller mills that used to crush grain. The Mill now serves as the site of the Bentley Gallery. Over 7 million viewers watch the evening news on CBS.

Just two weeks later an article on Snowflake was published in the Sunday supplement known as American Profile.  Distributed largely in the midwest, the magazine boasts a circulation of 10 million.

Around the same time, and much closer to home, Vermont's most important newspaper, the Burlington Free Press, featured Bentley in a large two page feature. Well known local reporter Susan Green interviewed Duncan Blanchard and myself for the article. With a circulation of about 30 thousand, the modest distribution is emblematic of Bentley's own humble beginnings.

The three stories had the potential to reach an incredible 17 million people! Bentley could have scarcely imagined such wide spread recognition when he did his speaking tours around the Northeast. Or when his book had it's small run published in 1931. The stories follow features in the past seen on TV Espana, WBZ Boston, Vermont's WCAX-TV, Vermont Public Television and Cable Access Programs.

Blair Williams and Wilson Bentley by  Duncan C. Blanchard

(April 24, 2007)

On a warm summer’s day in August, 1966, with popcorn clouds sailing east from over Lake Champlain, I drove from Burlington to Jericho to begin my quest to learn all that I could about Wilson Bentley, the Jericho farmer who in 1885 made the world’s first photographs of snowflakes. During the 1920s, at the height of his fame, he was known around the world as The Snowflake Man.

I first heard of Bentley nearly twenty years earlier, in 1947 when I was working at the Research Laboratory of the General Electric Company in Schenectady, New York, trying to develop a way to measure the sizes of raindrops. One day Vincent Schaefer, the discoverer of dry-ice cloud seeding, showed me an article he thought would interest me. Indeed it did. It was Bentley’s 1904 article about his ingenious flour-pellet technique to measure raindrop size. He was the first American scientist to measure raindrop size and used that information to deduce how raindrops are formed high up in the clouds. I put his article in my files, and years later after learning about his incredible feat of using a microscope to photograph snowflakes, decided to write articles or even a book about this amazing farmer-scientist from Jericho.

As I drove into Jericho, my first introduction to Bentley was a state historical marker by the roadside that said “Snowflake Bentley, Jericho’s world famous snowflake authority.” From there I made my way inland to that part of Jericho known as Jericho Center, snuggled up against the base of Mt. Mansfield, Vermont’s highest mountain. I went into a general store on the village green and asked where I’d find someone who knew Wilson Bentley. “Wilson who?” said two men relaxing in the store over coffee. I said: “Well, he used to be known as The Snowflake Man” “Oh yes, we’ve heard of him. He was a crazy guy. He spent all his time taking pictures of snowflakes.” The woman running the store knew of Bentley and said I should talk to his niece, Amy Hunt, who lived nearby.

I spent a delightful hour with Mrs. Hunt talking about her uncle, but before I left she said I must talk to Blair Williams, who was Chairman of the Department of Home Economics at the University of Vermont in Burlington. I wrote to Blair in September. She soon replied, starting a happy exchange of letters that continued for the better part of the next thirty years. [All of the material enclosed in quotation marks represents only a part of the letter]

She wrote: “I was delighted to receive your letter concerning your interest in Wilson Bentley. I wish I could be of some real help to you in gathering together material on his life and work. Unfortunately, as so frequently happens, his amazing skill was not recognized at a time when information concerning him was readily available. It does seem unfortunate that a man whose reputation has become worldwide is so little known in his own town and state. Miss Martha Caldwell of our related Art area, and I, have been trying, through the past few year, to gather additional information about his life and work but lack of time has curtailed us. “

Blair had been interested in Bentley long before I first wrote to her. From time to time she wrote long letters, including drawings, to friends and family. She called the letters The Cilley Hill Mail, Cilley Hill being the hill she lived on in Jericho. Her letter of March 1965 had a full page devoted to Bentley. She told about his life, the struggles he had in learning how to use his microscope and camera, and his perseverance in face of his father’s opposition to his work. Blair concludes her letter on a sad note:

”Jericho had hoped that the [100th] anniversary of his birth might be recognized by a commemorative stamp. It seems, however, that the Citizen’s Committee [of the U. S. Postal Service] felt this man’s work was not of sufficiently widespread interest to merit this distinction. “

In January 1968 Blair wrote to me that: “. . . along with Martha Caldwell I spent an afternoon taping some reminiscences of Mrs. Hunt. The Wilber Library [the University of  Vermont] will transcribe the tape.”

A month later Blair, in a whirlwind of activity, wrote a script not only for a Bentley program on Vermont ETV, but for talks about Bentley at churches or any other group that wanted them. Her enthusiasm for the work was clear when she wrote: ”You may be interested in the very rough notes that I have used in my two talks. The slides that were used of course added to the zest. The 2 x 2s made for the television program turned out very well and are now available for additional presentations. I am trying to enlarge the collection of slides. The snowflakes are especially exciting when thrown on the screen.“

After a Bentley talk in Jericho, Blair said: “We had an exhibit of some of the uses that have been made of snowflake designs as well as some of the things printed from the silk screens of the prints. Much interest was shown. We are even contemplating of going into business for the benefit of a Bentley collection.”

“I had a telephone call from a man [probably Arthur Pratt] who lived on the farm next to Mr. Bentley as a boy. I will have a talk with him, for he is anxious to relate some of his memories. I will see if I can tape his tales or keep a close record which he can later edit.”

In May, 1969, Blair sent me “two of the newest silk screen prints made from original prints of Mr. Bentley. A 4-H group in town has become interested and are working on some kind of an exhibit for the town hall—at long last!” And in September they applied for a grant from the Readers Digest Foundation to promote interest in local heritage. The grant was approved, and the girls began to gather information on Wilson Bentley.” What Blair did not say in her letter or in her later articles on the project or other projects was that she was the one that got the girls interested in the Bentley project, and then became the guiding light to keep the project moving along. This was typical of Blair, to keep herself in the background, and let others take the credit.

During a trip to Jericho in the summer of 1969 to interview people about Bentley, I finally met Blair. She was delightful. Her enthusiasm not only for Bentley but for Jericho history in general was quite evident. Words came tumbling rapidly from her mouth and confirmed what her letters had told me, that she was a whirlwind of knowledge and ability to organize projects. This was the first of several occasions that I had the privilege to meet this human dynamo.

Late in December she wrote: “Tuesday next the 4-H girls and I will be doing a 20-minute ETV program – pretty much a repeat of the earlier one, though the silk screening that the 4-Hers have done will be new.” On the program Blair showed a part of a taped interview with Howard Wagner. She said that “Mr. Wagner was a boy when Bentley was about. He does have some interesting tales to tell, and I am sure would enjoy the telling.” Indeed he would. A year later I visited him at his home in Burlington and taped many of his stories about Bentley. Some of them appeared in The Snowflake Man, my 1998 biography of Bentley.

In April 1971, on stationery with a large Bentley ice crystal embossed on the first page, Blair wrote: “How pleased I was to have a copy of your article—[My first Bentley story. It was in Weatherwise magazine] thank you so very much. My appreciation too for your kindness in considering that I was of help—mighty meager except for enthusiasm for what you are doing. This seems to be a Bentley year, and I have reaped considerable unearned credit! I’m sure you saw the winter issue of Vermont Life for which I supplied a picture reproduced from an earlier article. They evidently no longer had the originals. Later the Audubon Magazine did an article reproducing the snowflakes on a silver background. They are lovely.”

“This past Tuesday ETV did another program [on Bentley], this time with a script and a local narrator acting out part of the story. Mrs. Goldstein wrote the script and her husband did the acting. Their son supplied background guitar music and a song.”

“Probably the real satisfactory accomplishment of the week has been retrieving the material that Mrs. Alric Bentley lent out some four years ago. I tried last year and had a promise that the borrower would take them directly to Mrs. B. A few weeks ago Mrs. Hunt called. The girl that had never produced them, this time she brought them to the office, and once again she promised to take them to the owner. But at that point the material was in my hands and I held on! Tomorrow I will take it back to Mrs. B. Most of this I’m sure you have seen but will send a copy of the list later.”

In July 1971 Blair said: “I decided to return to full time teaching again, and so have been moving out of my administrative role [as Chairman of the Home Economics Department of the University of Vermont]. It’s pretty well accomplished now but has been time-taking. Hopefully I will also have a bit more time for extra interests and keep my home files in better shape. “

We exchanged no letters for the next year and a half, but in February of 1973, in a letter with a drawing of the Old Red Mill at the top, Blair wrote: “How pleased I was to open the current issue of American Scientist and find your article on Bentley’s work on rain formation. It’s just in time for me to bring it to the attention of a group I will show slides to this next Friday.”

“While you keep track, I have broadened horizons to include the Old Mill. Hopefully, if the good fairies are with us, the Jericho Historical Society would like to buy the building to use as a community center including space for as much of the Bentley materials as we can obtain. We have been working for about a year and are far, far from the goal that must be met, but we keep plugging. “

“You no doubt have already heard of Pearl Bentley [No, I had not], cousin of Uncle“Willie” who lives in Huguenot, New York. I learned about her recently from the people who purchased her home on Grand Isle. For a brief moment we thought we had found an unknown treasure chest.”

A month later, March 1973, Blair could hardly contain her excitement in her letter: “After the months of work our SUCCESS on town meeting day seems to have slowed me down[in her work on Bentley]. The town did vote to purchase the mill, and soon we will be working out the legal aspects of transfer and then rental back to the Historical Association. “

“I do want to work out a lecture on Wilson Bentley sometime in the coming year, hopefully using the Mill for the event so that we can begin to associate it with other facts of town history. Should you be thinking of any journeys in this direction, perhaps we could work something out. There are so many who would be interested. “

“Also I wonder about the possibility of having reprints, or perhaps reprinting your earlier article on Bentley’s life. Many of the people that stop at the Mill craft shop ask if there isn’t something they can purchase that gives some information about him.”

Included with her letter was a beautifully put together brochure describing the Chittenden Mill that had been declared a National Historic Site. Part of the brochure read:
          “Today the Chittenden Mill, now perhaps better known as the Old Red Mill, still stands five stories high on its same rock foundation as a landmark of the past. The Jericho Historical Society, a tax-exempt organization, would like to preserve the Mill and make it a community center. To accomplish this, the Society proposes that the town of Jericho purchase the Mill, together with the water rights and designated property consisting of approximately four and a half acres for lease to the Historical Society at a nominal annual rental.” I suspect that Blair played a major role in writing this brochure.

Not only did the brochure come with the letter, but for the first time she used a letterhead showing the Old Red Mill, a snow crystal, and a log cabin with the words “Jericho Historical Society.” The Society was wasting no time in moving ahead with plans to use the Old Red Mill.

Early in August, 1973, in reply to one of my letters Blair said she had been very busy at the Old Mill: “The construction really keeps me hopping. But this is not an adequate excuse for neglecting to say a very warm and appreciative thank-you for your generous gift to the Mill effort. We will tag it for some part in the Bentley exhibit.” [I do not recall how much I had given, but it came from some money given to me by a magazine that published one of my Bentley articles.]

Blair continued: “Saturday the official transfer of lease took place so there is a green light for proceeding with plans on restoration. The undertaking looks huge but less impossible all the time. The first month of running the shop was, we felt, very successful, and each week it improves and grows. Having something open and in action does a tremendous job in creating interest in the Mill.”

In an earlier letter I told Blair I’d be glad to let the Historical Society reprint and sell one of my Bentley articles. She said: “I have been investigating the best way of taking advantage of your offer on the reprints. It is most generous, and I will write again when I have had more time to talk with printers. We now have a Snowflake Room in the shop, and it is of course attracting considerable attention.”

Blair had asked me if I would talk about Bentley to the Historical Society. I said I’d be glad to. She writes: “Hope you have had word from the program chairman, for we do want to have an evening of your time, and I don’t want to let it drift along without a positive date. We can adjust to your schedule. “

I gave my Bentley talk to the Historical Society in mid November 1973, and later Blair wrote to say “how very much everyone enjoyed the evening spent with you.” Blair was always on the lookout for Bentley material, and would tell me about it in many of her letters. “Have you talked with a real estate man in Essex Junction by the name of Mudgett? His mother I understand had a letter from Bentley that he now has in his office.”

More than two years passed. I was getting more and more involved with my students and research at the University at Albany, and did little on the Bentley story, nor did I write to Blair. But Blair broke the silence when she wrote in January, 1976:
         “With the current copy of the Smithsonian and its article on ice crystals and Bentley, my mind turns to you as it has quite a number of times this fall. It’s been a longtime since I’ve had any word from you, and I keep wondering how things are, and if you have been able to find some time on your biography of Wilson Bentley. Somehow I resent others getting into print when you have put so much of yourself in gathering information.”

“Last summer Mrs. Hunt let me take a copy of a book (don’t have it here. It’s on the Hill,

I’m at the Mill) by a Japanese author. I believe you loaned him many of the Bentley articles. I have been trying to get one section translated for her: ‘The Road to Jericho.’ She is especially anxious to see it. A graduate student from Japan thought he could do it, but I’m afraid he will not get at it. I have a nephew who soon will be going to Japan on business. I’ve asked him to buy another copy, and suggested he translate it in his spare time. “

“Did you ever talk with the couple who lived in Bolton or Richmond? The man is an artist and they knew Bentley. I have a news clipping about them and keep hoping for time to look them up.”

“Activity at the Mill continues. We are about to advertise for bids on the first real restoration work. The shop prospers and enthusiasm for the project seems to grow. It’s all very satisfying.”

I wrote to Blair two weeks later and told her that the author of that book is Dr. Kobayashi, a friend of mine. “I met him in 1965 when I attended a cloud physics conference in Tokyo and Sapporo. We exchanged many letters as he prepared his manuscript. I did not try to get a translation, as I doubt I would learn anything new. He said that much of what he says is what he got from my three Bentley articles, plus copies I sent him of some of Bentley’s work.”

Blair replied late in February 1976 and wasted no time in telling me of her latest involvement in the Bentley story. Enclosed was a page from a January issue of Time  magazine. She said: “Perhaps you saw this ad in Time of the First Vermont Bank [I had not] with the picture of Bentley and a background of snowflakes. I was unaware of the reference to the Reverend Henry Crocker and so wrote to inquire about the source. They told me it came from material at the Vermont Historical Society which as yet I’ve not had time to investigate. I can’t remember even hearing the name of Crocker, though I find there are some still living in Fairfax. I think the Rev. Crocker went to Chester and was evidently one of the leading lights in the formation of the National Survey there.”

[I later told Blair that I had heard of the Rev. Crocker back in 1967 and wrote to his grandson who was president of the National Survey. He told me that his grandfather did correspond with Bentley though he had none of the letters. The Time ad said that a magazine article about Bentley by the Rev. Crocker brought Bentley the recognition he deserved. I am skeptical about this, as I am about a similar claim by Henry Seeley, a civil war veteran.]

Blair continued, always with an eye to getting some Bentley material for the Old Red Mill: “Are you familiar with the Bentley exhibit that has been on display at the State Museum in Albany? I understand it has been taken down. I wrote them to see if it might be an exhibit that we might inherit if they no longer plan to use it. They wrote to say it is to be kept, but could be made available for an exhibit if we would like it for a limited time. I am wondering if it would be worth bringing to Jericho, or whether we may have duplicates of their collection. Any suggestions?”

I replied and said I had seen the exhibit before it was taken down. I wrote that it “. . .consisted of 5 or 6 large glass-covered frames that contained 20 or 30 of Bentley’s snowflake pictures. Each picture was quite small, and because of the way they were displayed, I did not find them attractive. I doubt that it is worth your time and effort to get them to Jericho.”

Blair ended her letter: “And finally, how practical would it be, and would it be possible, to have a copy made of the Bentley film? We are hoping to work out some kind of a showing of our historical past this summer, probably August, and of course Bentley will provide much of interest.”

Blair was referring to the long-lost Bentley film that I had discovered several years earlier, and therein lies an interesting story. Some of the first people I interviewed told me that a movie had been made of Bentley, but when I asked them who did it and where it was, they had no idea. In the summer of 1971, when I was in Weston talking with Alice Bentley Hamalainen, I said I had heard rumors about a Bentley movie, and asked if she knew anything about it. She said, “Well, I’m not sure but there’s something I’ve had in the back of my closet for many years. I’ll see if I can find it.” She went to another room, and I could hear her as she pulled boxes and other things from the closet. She returned with a small dusty, burlap bag tied at the top. I untied it and pulled out a canister containing some 35-mm movie film. Could this be it? I was excited as I took the reel of film, unwound some and held it up to some light. I could see a figure on several frames. Yes, this had to be long-missing movie of Bentley! I was certain of that.

I had 16-mm copies made for Blair and the Jericho Historical Society, the State Historical Society in Montpelier, and for Mrs. Hamalainen. The movie, only a few minutes long, was made about 1917 when photographers from Pathe News had Bentley take his camera out in the yard beside his house. Bentley showed how he picked up a snow crystal and placed it in front of a microscope that was attached to his camera. They had him wear his best dress-up clothes, white shirt and collar, black tie, dark overcoat, and a soft felt hat. Bentley must have fussed and fumed over this, as he never worked out of doors with his camera, and he certainly never dressed up when he did his photography. But his anger must have reached record levels when the photographers thought it would be nice to have snow falling while their cameras were rolling. But it wasn’t snowing that day, though some snow was on the ground. No problem. The movie crew scooped up snow, put it into a basket, and had Bentley’s nephew, Alric Bentley, go upstairs in the house and throw handfuls of snow out an open window.

It wasn’t what the movie people had in mind. Instead of having snowflakes falling slowly and uniformly over Bentley, large chunks of snow fell like hailstones, hitting his hat and shoulders producing splashes of snow that dotted his hat and coat with white blotches. Not to worry. Snow was snow. The camera kept rolling and captured a disgruntled Bentley.

In 1977 Blair was the prime mover behind a drive to get the Postal Service to issue a commemorative stamp for Bentley and his snow crystals. She had her eye on the stamp being issued in 1980 just in time for the 1980 Winter Olympics in Lake Placid. I told her I would help by having some scientists, all experts in the study of snow crystals, write letters urging the Postal Service to issue the commemorative stamp. I wrote to six scientists I had met at conferences and asked them to send the letters to Blair. They were from Japan, Australia, Germany, England, and the United States.

In October 1977 Blair wrote: “I received a very nice letter from Dr. Aufm Kampe .“ [Aufm Kampe, a German scientist who was working in the United States, once told me that during WWII he was in the German Air Force, but was allowed to make measurements on the variety of snow crystals in different storms. He was aware of and greatly admired the work of Wilson Bentley.] Blair continued: “Despite the lack of encouragement from people who have tried to get the stamps, I find it hard to believe we could be turned down if this kind of support comes from the other scientists. I am also going to pursue some of the Olympic people and the ski industry here in Vermont. If nothing else, it will make an interesting file.”

The other scientists Blair mentioned did write letters praising Bentley and his work and made it clear that he was known and admired far beyond the borders of the United States. They highly recommended the issue of a commemorative stamp. But it was not to be.

In December 1977 Blair wrote: “A week ago we did a Bentley TV program. This time, Mary Lighthall, who has photographed some snow crystals, talked about the difficulties involved. It added a nice dimension. We also used the Bentley movie. Mrs. Hunt[Bentley’s niece] saw it. She could hardly believe her eyes. I understand that a Burlington photographer was with Pathe'. Now I’m trying to find out if possibly he was involved in the movie.”

Nearly two years passed before Blair and I again exchanged letters. In June 1979 Blair wrote: “The shop [at the Old Red Mill] is once again low on your reprints. Is it possible to again use the plates and have more printed? I am scared to death to be responsible for them, but there is nothing better than your article to put in the hands of interested people.”

“My second question concerns a follow-up to our slide program on the life of Bentley. When I show this to the upper level school children, I keep thinking that there should be a second presentation which goes into the scientific side of Bentley’s work, including the follow-up referred to so often in the letters that came concerning the commemorative stamp. It sounds like an ambitious undertaking and would of course entail the help of scientists. If you think it not too impossible an idea, I could write up a proposal to the AAAS [American Association for the Advancement of Science] to see if there might be help in funding such a project.“ This was vintage Blair. She showed that dogged determination to aggressively pursue any possibility to reach her goal.

I replied a month later, and said of course she could use the plates once again. As for the proposal to the AAAS, I was not very encouraging. I wrote in part: “Does your new proposal refer to a slide program with a bit more of the science Bentley did, or were you thinking of a booklet that could be sent around to the schools? In either case, as you say, you would need the help of scientists. The difficultly as I see it, is that while there are a great many scientists, both in the United States and elsewhere, who are experts in atmospheric physics, there are very few who have the interest to go back half a century to study the works of people like Bentley. As I said in my first Bentley story, which you have, he did little creative work after about 1910. I think this is because nobody paid any attention to his work. In short, he was ahead of his time. Bentley had been bypassed. It was a pity, and I suppose this is one reason why I have such an interest in Bentley. Why, in view of the many novel scientific ideas he had, was so little attention paid to him by other scientists? I hasten to add that the lack of attention was only from the scientific world. The general public, especially during his last ten years, was well aware of the splendid photomicrographs he took.”

“I think that, other than myself, you will be hard pressed to find more than one or two others who have read the Bentley papers. Thus, were you to write to the AAAS for help, I doubt that they would know where to turn. Perhaps you had something else in mind when you spoke of ‘funding such a project.’ Perhaps models of his experiments? This is what the Buffalo Museum of Science has in mind, an exhibit of his work and ideas. They would need many thousands of dollars to get it off the ground. But if you just wanted some ideas about Bentley’s science and how it fitted into the atmospheric sciences of today, then maybe I can be of help.”

From March 1983 through February 1986 my letters from Blair appear to have been lost, but I have copies of four of mine to her from that time. In March 1983 I thanked Blair for sending me a copy of a letter about Bentley that years ago had been submitted but was rejected by Reader’s Digest. In November I sent her a reprint of my article on Bentley’s auroral observations. A month later I wrote to thank Blair for telling me about a piece on Bentley that will appear in the spring on the CBS TV show American Parade.

Nearly two more years passed. In February 1985, in replying to what may have been a detailed letter from Blair, I said: “From the sounds of things you people must have had a fine celebration for Bentley’s 120th birthday. The announcement of the party (which you enclosed) mentioned a showing of Bentley’s life story, ‘Bentley’s World.’ Is it a movie?” I thanked Blair for a snowflake calendar she had sent to me.

In May 1988 Blair wrote: “Sorry to be so long in sending you these local papers featuring our renewed effort to get a Bentley stamp. . . . Yesterday I had a note from Toshio Kuroda telling me of the death of Professor Kobayashi. Previously, he had sent me a copy of the monograph Snow Crystals by Kobayashi and Kuroda. I was pleased that we were sent a copy.”

“We have sent many petitions to Washington, and several more publications are in the works. Of course there has been no response from the Stamp Committee.” Then wanting to end on a positive note she wrote: “We had another great Bentley exhibit at St. Johnsbury.”

Two weeks later Blair wrote that: “The Chittenden County Stamp Club has been plugging for a Bentley stamp and we will co-sponsor their annual spring meeting in June.

Would you be willing to go over the enclosed and make any changes you see, for use in the one-day cover they will have available?”  

I replied with a few minor changes, but I went on to say that: “I’ll send a letter to the U. S. Postal Service, and I think I can get three or four others here at the Atmospheric Sciences Research Center to do the same. Do you plan to send the letters I got for you in 1977 from scientists around the world? Though they were dated long ago, I think they will help.”

I plan to visit Jericho this summer in preparation for my biography on Bentley. Among other things, I will want to look at what the Jericho Historical Society has on Bentley,primarily the photographs, and to visit his old house once again to take more photos. I also want to tramp around the hills behind his house.

Blair invited my wife and me to stay at her home on Cilley Hill. We had a wonderful time. Blair arranged for me to see Jean Smith, who let me go through the Bentley files at the Jericho Historical Society. Some of the items about Bentley I did not have, but Jean later made copies and sent them to me.

In mid-January 1990 Blair wrote to tell me about the one-day issue of the Bentley commemorative envelope with the one-day cancellation stamp. She said: “The envelope and cancellation stamp are, I think, very good, Several orders have already come in from stamp collectors who have seen the notices in stamp publications.” At the end of her letter Blair told me about the weekend celebration planned for Friday and Saturday, February 9-10 for Bentley’s 125th birthday. She very much hoped I would come.

I did attend the Friday celebration, arriving at the elementary school as the crowd was gathering. There was snow on the ground and in the air, perfect for a Bentley celebration. There was excitement among the many children as they looked at the numerous beautiful displays of snow crystals and Bentley materials. A giant snow crystal was hanging high above the auditorium floor. Blair seemed to be everywhere, checking the presentations, helping children, and even greeting visitors as they arrived. The big event planned for the evening was to be a slide presentation by a local meteorologist on weather and Wilson Bentley. But at the time the slide show was to begin, there was no meteorologist. Children were seated on the floor, anxiously awaiting the show. Blair asked me if I could say something about Bentley if the speaker does not show up in the next 5 to 10 minutes. Here I was with no slides, no notes, or any visual displays to help me tell about The Snowflake Man. After about 10 minutes, there was still no speaker. I looked at Blair and said “OK here I go” and walked up to face the children and their parents. I suddenly decided not to tell about Bentley and his snowflakes, especially sinceI had no slides to show, but to tell them about how Wilson Bentley became the first person in the United States to measure the sizes of raindrops. Although they knew about his snowflake work, I suspected they knew nothing about his pioneering work with raindrops and how they formed high up in the clouds. I was several minutes into the raindrop story when, to my great relief, the scheduled speaker arrived. He set up his slides and soon took over. I was not there the next day, but Blair wrote and said: “Today was wall-to-wall children and standing adults. It was a huge success.”

A few months later Blair wrote to say she had talked to a woman in Essex Junction who:“remembers Bentley coming to the schoolhouse to show his lantern slides and talk to the children. She said she really didn’t remember much, but as she talked she seemed to remember more than she expected. If you are up this way again, it might be worth giving her a call.” I had just retired from the University at Albany and was heavily involved in research for a biography of Bentley. I made a note of Blair’s information but never acted on it.

Late in January 1991 I wrote to Blair: “By now I suppose you are aware I will be at Trinity College in Burlington on 13 and 14 March to talk about Bentley.” Blair replied a week later: “Indeed I do know about the program at Trinity College in March. We did a Bentley program on Across the Fence [television program on stories and places relating to Vermont] this past Wednesday and gave it publicity. T hen this afternoon I spoke at the Burlington Library.

My Bentley presentation at Trinity College went well, but more than that, as I wrote to Blair: “You and Gloria [Stoddard, author of Snowflake Bentley, a 1979 biography of Wilson Bentley] did a fine job in arranging the display of Bentley materials . . . a most beautiful exhibit indeed. I was glad to see someone there on guard at all times. Otherwise it would be far too easy for some unscrupulous person to walk off with some of the priceless items on display.”

At Trinity College Blair and I talked about how nice it would be if the Jericho Historical Society (JHS) could purchase the two microscopes used by Bentley. Blair wasted no time in taking action. A week later she wrote: “I just called Jean Smith [the JHS archivist] to ask about the person who had the Bentley microscopes. She is Mrs. Roberta Carr of Carr Books in Concord, New Hampshire. She had them listed for sale a year ago for $17,000, a price much too rich for our blood.”

On May 1 Blair wrote again: “I talked with Jean Smith this morning about the $1,500 that IBM has given toward the purchase of the Bentley microscopes. We could not raise the rest, so she was inquiring of IBM what to do. Nice people. They said to use it some other way. Jean had written to Mrs. Carr but never heard back.“

Blair had given me Mrs. Carr’s address and phone number, so I called right away. I eventually learned she was representing Mrs. Agnes Manson, the owner of the microscopes. Mrs. Manson’s uncle was Matti Hamalainen, who had been married to Bentley’s niece, Alice (Bentley) Hamalainen. I told Blair that: “At first Mrs. Carr was very reluctant to give me Mrs. Manson’s address and phone number. She said there should be no question about the workings of the microscopes since Bentley described them clearly in his articles. I convinced her, finally, that I had read some 60 of Bentley’s articles, and that questions remained as to the exact means of the focusing, and the only way to resolve them would be to look at the microscope itself. It was then that she told me that Mrs. Manson lived in Chester, Vermont.” She gave me the address and phone number.

 I called Mrs. Manson and found that the asking price for the two microscopes had dropped from $17,000 to $10,000. I visited her in June 1991. It was exciting to see and hold the microscopes that Bentley had worshiped and used so effectively for 46 years. I wrote to Blair about my visit: “I now fully understand how he used the wooden discs and strings that ran from behind his camera to the microscope to get a sharp focus on the glass plate negative. The fine-focus knob on his microscope was in a much different position than it is on modern day microscopes. I had not realized this before, thus my confusion.”

Over the next few years JHS, while anxious to get the microscopes, was in no position to do so. The Society had purchased the Old Red Mill in Jericho and was trying to renovate it. What money they had was used in several projects, especially one to restore the outside of the Mill.

What happened next is a story of perseverance and determination by several people in the JHS to bring the Bentley microscopes to their rightful home in Jericho. In March 2007 Ray Miglionico [the archivist who took over from Jean Smith] told me what had happened. “In 1998 I received a call from a person in the Vermont Historical Society about a contact from one of Bentley’s descendents offering to sell the microscopes for$10,000. They apparently didn’t have the funds to purchase them so they declined. They said that Mrs. Manson told them another buyer was interested. I brought this to the JHS Board in which Blair was an active participant. It was decided that a Special Edition Print would be issued to try to raise the funds necessary for the purchase. Wayne Howe [Vice-President of JHS] and I went to Mrs. Manson to see the microscopes and made an offer to buy them if given enough time to raise the funds. We promised to pay $5,000 by the end of the year and the rest at a later date if she would not sell them before then. She agreed.”

 “We set out to promote the project to our mailing list of people who had purchased Limited Edition Prints, and we were lucky to have the Burlington Free Press do a small article about the fund raiser. I remember a hot July day when a bunch of volunteers, Blair included, starting stuffing envelopes with reservation forms for the new print. The plan was to have people reserve prints by giving a deposit to reach the $5,000 commitment. The prints would be ready for pickup by customers in December. The response was overwhelming! Not only did we reach commitments for the $5,000 but enough to purchase the microscopes outright. In November Wayne and I went back to Chester and brought the microscopes back to Jericho, along with many other items which went with them. There was great satisfaction when people came to pick up their prints, and were able to see the results of their support.”

We now return to March 1992, when Blair wrote: “This past week Ray (our archivist) and I met Stan Kerschner, JHS member, retired IBM’er, and a photographer. Quite a number of years ago he approached me about doing another Bentley video. I never seemed to find time to make the follow-up contact until now, and thank goodness he had not lost interest. “

“The more I go out to talk about Bentley, the more I regret the limitations of coverage on the other aspects of his contributions to science. What Stan and I talked about was giving something that would compliment Bentley’s World [title of Blair’s Bentley talk] but would concentrate on his other accomplishments (as well as snow crystals) of a scientific nature. He was enthusiastic and departed with background reading. We made copies of some of Bentley’s papers, some of yours, and the various tapes we already have. Kerschner has set an October date to have a script in place. We have given him your address and phone number, so I expect you will hear from him.” [I never did hear from him]

Two months later I heard from Blair again. “Since giving your name to Stan Kerschner, I’ve not heard back. He did not think he would have time to do much, but planned for October, so I am sure he will be in touch. We have some IBM money that will be available for him so that will help, I hope.”

No letters were exchanged during the summer and fall of 1992, but late in November Blair sent me a collection of sketches of Jericho people from times past. She said: “Here is the Bicentennial effort [the state of Vermont]. As you will find out all too soon, the Bentley piece could have been better. I was glad, however, to have some of the students in the high school participate. We had money left over from our other activities so I am quite free to send out copies to people such as you at no cost. What a pleasure.”

“There is a request I’d like to make of you, despite the pleasure expressed above. We are gathering content for our next Historical Society Newsletter. I’d appreciate some input from you. It would be nice, I think, to have a brief article on Bentley’s aurora sightings, especially the blood-red one of February 13, 1892, one hundred years ago. It seems like a good way to keep Bentley before our readers.” [Over forty-nine years Bentley observed and recorded 634 auroras! In September 19, 1920, Bentley sent a letter to Dr. Charles Brooks, editor of the Monthly Weather Review, containing a list of all these auroras. He said: “Of all these I have seen, the blood-red one of February 13, 1892, impressed me most strongly.”]

The day after Christmas 1992 I sent Blair my story about Bentley and his observations of the auroras. A month later Blair thanked me for the story. She wrote: “I must send a copy to our weather reporter [Jericho Reporter], for it should make an interesting comment as we near the 100th anniversary of Bentley’s blood-red observation.”

Late in July, 1992, Blair wrote: “We have made good progress at the Mill. We have funds and a contract in the works for the redo of the roof. Work should start Sept. 1. What a step forward that will be.”

We exchanged several letters after that, but the letters from Blair appear to have been lost. In February 1994 I wrote Blair: “The latest Jericho Reporter just came my way, and right on the front page is the announcement of the award given to you by the Preservation Trust of Vermont. Congratulations. You surely deserved it for all you’ve done for Jericho and Vermont history.”

Blair, always on the search for information about Bentley, had asked me if there is any reference to the sale of Bentley’s snow crystal prints to Tiffany’s. I did some searching myself and found that Lillian Loveland in her 1922 Bentley article in The Vermonter, quoted Bentley: “Some years ago, I sold two hundred of my photographs to Tiffany’s, the New York jewelers, and I understand they designed some very beautiful brooches and pendants using the snow crystals as patterns.”

The Snowflake Man, my biography of Wilson Bentley, was published in the fall of 1998, and I sent a copy to Blair. In the acknowledgements I said: “I am indebted to the indefatigable Blair Williams, who for more than twenty-five years has been building up the Bentley collection at the Jericho Historical Society, and has not let the citizens of Jericho or the world beyond forget Wilson Bentley. I have treasured the exchange of many letters with Blair.”

I saw Blair for the last time in July 2000. A week later I wrote my last letter to her: “It was good seeing you last Friday. I’m delighted that you are able to give encouragement to Ray Miglionico and others to carry on at the Jericho Historical Society what you started so successfully many years ago.”

Blair died, at age 96, on October 27, 2006 in the stone house she built on Cilley Hill in Jericho.

No one will ever completely replace Blair Williams. She was a whirlwind, dynamic, energetic, and unwavering in attempts to accomplish projects she thought were worthwhile. In her professional life she taught and was Chair of the Department of Home Economics at the University of Vermont, and in retirement wrote and published the history of the department. But perhaps she will best be remembered for her many achievements in her hometown of Jericho. In addition to her work on the Bentley story, she was a charter member of the school board, and an initiator in the Jericho school hot lunch program. She donated land for the Jericho Center library, and started and for thirty years coordinated the First Congregational Church chicken pie suppers. She was heavily involved in the acquisition and restoration of the Old Red Mill, and helped set up the Old Mill Craft Shop.

I was fortunate to have had Blair as a friend for nearly forty years.

Bentley’s Most Singular Observation by Jon Nelson

You don’t have to look at frosted surfaces for very long before coming across something like the following.

The picture shows a large ice crystal amid a roughly uniform sea of tiny frozen droplets. Between the large crystal and the frozen droplets lies a clear ice-free zone, a dry moat around an island of ice. Sometime prior to 1907, Bentley took notice of this moat. Writing in the Monthly Weather Review in 1907, he wrote

One of the most singular, and doubtless most important, phenomena that occur in connection with the formation of window frost is this: The true crystalline varieties of window frost ordinarily, apparently, repel the minute liquid particles or droplets of water that frequently collect like tiny dew-drops on the glass, and freeze in granular form thereon.

The reason he found the phenomena so important was explained next:

This phenomenon is endowed with the greatest interest, because the repulsion operates also within the clouds while snow crystals are in process of formation, and hence has an important bearing on forms and structure of snow crystals, and in keeping them free from granular deposits of a like nature.

The appearance of a physical repulsion between the ice and the surrounding droplets (before they froze) is indeed strong. So, in the next paragraph, he speculated about a possible mechanism.

We can only conjecture as to the cause of this most interesting phenomenon. It may be of an electrical nature. Possibly both the snow and frost, and the liquid cloud or dew droplets, possess an excess of the same kind of electricity, positive or negative. If so they would naturally repel each other.


It was just a brief bit of speculation before immediately returning to his main objective, which was describing his observations of frost. Now the mechanism he described is wrong, but he was right on the mark with the idea that the phenomenon was important. Indeed, the same phenomenon occurs in clouds, playing a major role in the formation of rain.

The real reason for the dry moat lies in the nature of liquid and solid water. At a given temperature, water molecules evaporate from liquid at a faster rate than that from ice. In other words, ice holds onto its molecules a little more strongly than the liquid. You can picture the scene as follows: Initially, the glass surface was covered by tiny dew droplets, with each one of them gaining and losing molecules in roughly equal rates. So, the droplets show no net growth or evaporation. Then one of the droplets freezes.  Although the surrounding vapor condenses on the crystal at about the same rate as that on the droplets, the crystal gives up fewer molecules to evaporation. So the crystal experiences net growth from the vapor, while drawing a net amount of vapor from the surroundings. This drawing of vapor to the crystal reduces the amount of surrounding vapor (i.e., humidity) and so the nearby droplets no longer have a balance between condensation and evaporation: they have net evaporation and vanish. In this way, a dry moat forms around the crystal. Later, the other droplets freeze.

The above explanation was probably first proposed by Alfred Wegener in 1911 after he too observed frost. Wegener, though most famous for his theory of continental drift, was by profession a meteorologist. Like Bentley before him, he proposed that the process would also occur in clouds. (Curiously, the next scientific article on window frost in 1939 by Ukichiro Nakaya, Masando Hanazima, and Kenzo Dezuno, also noted the dry moats around large ice crystals, but did not speculate on its origins.) And just as the process occurs in clouds, so too it will occur on other surfaces. For example, the image below shows dry moats on acar hood.

The lesson here, I think, is that study of something common and seemingly inconsequential (e.g., frost) may shed light on a far more important problem (e.g., rain). This is one of the things that distinguishes science from engineering. In this case of the dry moat, Wegener suggested that an ice crystal within a cloud of droplets would grow at the expense of the droplets, and this process would lead to large crystals that later precipitate. In the 1930s, Tor Bergeron expanded upon Wegener’s mechanism, showing how the process would lead to rain. This rain-production mechanism is thought to produce most of the rain in midlatitudes. (For more about the Bergeron rain mechanism and its relation to Bentley’s observations, see Duncan Blanchard’s book1.)

Further observations of the dry moats has other applications to snow crystal growth in clouds. For example, the shape of the moat tells us how the water vapor gets distributed around a growing crystal. The distribution of vapor, in turn, influences the crystal shape and growth rate. Notice in the image below how the ends of the column-shaped crystal lie closer to the droplets. Indeed, the ends have grown into the droplet region. This means that the faster-growing points of a crystal can grow into regions of higher humidity. By growing into regions of higher humidity, they can grow even faster. This effect largely explains why the familiar snow-crystal star is the fastest-growing natural snow crystal. In second place lies the long, thin columns and needles.

So, as Bentley surmised, the dry-moat phenomenon does have an important bearing on forms and structure of snow crystals. His observation was indeed most singular.

1. Duncan Blanchard, The Snowflake Man: A Biography of Wilson A. Bentley, McDonald & Woodward Publishing, Blacksburg, Virginia, 1998. See chapter 11.


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Snow Crystals Vol. #17 March 14, 2011


Editors notes
Johannes Kepler’s Six-Cornered Snowflakes by Duncan C. Blanchard
Bentley Work Featured at Saint Lawrence University by Wayne Howe
Why six? by Jon Nelson
News From The Gift Shop
by Ray Miglionico

Editors note by Peter Wolf

After a slow start to the winter snow season , Bentley would have been in his glory with the snowiest February on record in the Jericho area. On March 4th Jericho received 30 inches of snow, the largest March snowfall on record and third largest storm in history in the Burlington area. Other notable weather happenings in Jericho were wind gusts up to72 mph and a 44 hour power outage, following a number of fierce wind storms. One can only wonder what Bentley's take would be on the current weather extremes that we are experiencing.

Is six your lucky number ? Well it is today as we have two article on the six sides of snow crystals. Duncan Blanchard gives us a whimsical look into Johannes Kepler and his pondering of the nature of snow crystals. Jon Nelson gives us a much more in-depth explanation and more thoughts to ponder.

Wayne Howe tells about Bentley work featured at Saint Lawrence University. This is just one of many exhibits of Bentley's work in the past year including Chicago & New York. We also continue to receive image requests for text books and testing materials from various parts of the world. The images and knowledge of Bentley's work lives on still today.

Johannes Kepler’s Six-Cornered Snowflakes by Duncan C. Blanchard

Johannes Kepler was a great mathematician and astronomer. He is perhaps best known for his discovery of the three laws of planetary motion. He introduced the first two in his 1609 book Astronomia nova (The New Astronomy). His first law is that the planets move in elliptical patterns around the sun, not in circular patterns. Years later Isaac Newton, using his theory of universal gravitation, confirmed Kepler’s three laws.

Kepler was born in Bavaria, Germany, In 1571 he was a graduate student at Tubingen University. He received only A grades, and the university senate noted that: “Because of his unusual mind, something special may be expected from him.”

Something special indeed! He immediately grasped the beauty of the ideas of Copernicus. But he wanted to know why the planets moved faster when they were close to the sun, and was there any connection between the size of their orbits and the time it took to move around the sun. He tried to answer these questions in his first book Mysterium cosmographicum (Sacred Mysteries of the Cosmos).

This book led to his meeting Tycho Brahe, probably the greatest observational astronomer who ever lived. Brahe had moved from Denmark to Prague in 1599. Kepler was offered an apprenticeship with Brahe, and later through Brahe’s influence became the Imperial Mathematician to Emperor Rudolph II. Kepler’s friend and patron at the Emperor’s court was John Matthew Wacker von Wackenfels.

Kepler was now passionately devoted to studies of mathematics and astronomy. He said: “If there is anything that can bind the heavenly mind of man to this dusty exile of our heavenly home, then it is verily the enjoyment of the mathematical sciences and astronomy.”

Late in the year 1611 Kepler wanted to give a New Year’s gift to his friend at the court but was unable to think of anything that might please him. Still deep in thought as he walked home, it began to snow as he crossed the Charles Bridge in Prague. He later wrote: “I was mortified by my incivility in having appeared before you without a New Year’s gift, except perhaps (to keep playing the same chord) the one I always bring you---namely, Nothing,

Nor was I able to think of something that, while being next to Nothing, would yet allow for subtle reflection. Just then, by happy occurrence, some of the vapor in the air was gathered into snow by the force of the cold, and a few scattered flakes fell on my coat, all six-cornered, with tufted radii. By Hercules! Here was something smaller than a drop, yet endowed with a shape. Here indeed was a most desirable New Year’s gift for the lover of nothing, and one worthy as well of a mathematician (who has Nothing and receives Nothing) since it descends from the sky and bears a likeness to the stars.

“Let us then go back to our patron while the little gift still lasts, before the warmth of my body dissolves it into nothing. “

And oh, what a portentous name it has, this thing most pleasing to Wacker, the lover of Nothing! For if you should ask a German what nix means, he will respond: “nothing, “ if he knows any Latin.

“Accept, then, with a cheerful countenance this tribute of Nothing, and if you are sensible hold your breath, that you may not end up again with nothing”

Here, it would appear, that Kepler with his sense of humor was engaging in a bit of word play. The German word for nothing is nichts, which is pronounced the same way as nix, the Latin word for snow.

Kepler continues: “But all joking aside, let us get to work. Since it always happens, when it begins to snow, that the first particles of snow adopt the shape of small, six-cornered stars, there must be a particular cause; for if it happened by chance, why would they always fall with six corners, and not with five, or seven, as long as they are still scattered and distinct, and before they are driven into a confused mass?

So what might be this cause? Kepler says: “When I recently had a conversation with someone on this subject, it was first decided between us that the cause was not to be sought in matter but in some external agent. For snow is made of vapor, and when vapor first rises from the earth on account of its heat, it is a continuous substance, almost like a liquid, and is not divided into individual little starts of the sort we are considering.”

Having concluded that the cause was in some external agent, Kepler writes that “. . . it remained uncertain what the agent might be, and how it acts. Is it through an inherent form, or rather by building from without? Does it form the six-cornered shape according to the dictates of the material, or rather out of its own nature, to which would be innate either the archetype of beauty that is present in the hexagon or an understanding of the purpose which the figure serves?”

Kepler gives a detailed discussion of the hexagonal structure of a bee’s honeycomb and the seeds of a pomegranate. But he concludes that the mystery still remains. “I set out these considerations only as examples, so that we may be better prepared and trained in examining the shape of the six-cornered snowflake.”

He goes on to consider what happens “. . . in hot baths, when the rigor of winter comes up against broken windows. At these narrow passes there is a struggle between cold air and steam, and when they come into contact, the heat rises and the cold descends. . . Whatever steam settles on those edges is immediately frozen. And since a like amount of cold takes its place, whatever additional steam settles on the frost will also freeze, in continuous deposition, for as long as cold air intervenes and finds a direct way in. It is because of this alternate rushing in and out that the frosted layers of vapor obtain striations and sharp radii.

“Nothing of the sort can be said about the shape of our little snowflake. For what entrance, what exit, what narrow openings, what struggle can there be in the wide fields of the air? I concede that in their fall from above through the steamy air there could be some accretion of little tufts from the surrounding vapors. But why in six places? What is the origin of the number six? Who shaped the little head before it fell, giving it six frozen horns? What cause establishes on that surface, at the very moment it condenses, six points for six radii to be connected all around?

“As I consider this, I begin to wonder: Why are the radii not arranged spherically in every direction? Why, if internal heat is responsible for this, does it operate only on a plane surface? For heat distributes itself uniformly in all places, and is not present only on a flat surface of vapor. “

Kepler leaves this topic and goes on at great length to other considerations. He discusses what he calls a vital or formative faculty in plants. He writes that . . . “others may object that individual plants possess their own vital faculties because each plant body stands entirely separate, and that on this account it is no wonder that each plant should receive a unique shape. In the case of snow, it seems ridiculous that each little flake should have its own soul, for which reason one should not conclude that the shapes of snowflakes arise in the same way as those of plants, from the work of a soul. “

Kepler must have smiled when he wrote: “Oh, truly life is dead without philosophy! For if only the adulteress in Aesop’s fable had known of this formative faculty in the snow, she could have persuaded her husband that a snowflake had made her pregnant, and would not have been so easily robbed of her illegitimate child by her husband’s duplicity. “

Kepler ends his speculation on the cause of the six-cornered snowflake by speaking directly to his patron von Wackenfels. “Since much remains to be said on this subject before we know the cause, I would rather hear what you think, my most ingenious man, than wear myself out with further discussion.”

Nothing follows.

The End.


Kepler was not the first person to notice the six-fold symmetry of the snow crystals. But he was the first to attempt an understanding by introducing a variety of new ideas and making analogies to natural objects such as the hexagonal shape in a bees’ honeycomb and the stacking of pomegranate seeds.

Who was the first? We will never know, but surely it must have been many tens of thousands of years ago when some curious, inquisitive creature, a member of our species Homo sapiens, first noticed the infinite variety of snow crystals and their six-fold symmetry. What caused this symmetry? It was to be found in the shape of the water molecule, but this was not known until 1929, more than 300 years after Kepler’s speculation on the six-fold symmetry.

It is possible that a lecture by Wilson Bentley on snow crystals was a motivation for Dr. William Barnes to discover the shape of the water molecule. In January 1925 Bentley gave several lectures in Montreal. Barnes, who was interested in the physics of ice, was in the audience. He had discussions with Bentley about the shape of snow crystals. Four years later he would make history by being the first to show by careful experiment that the water molecules in a unit cell of ice locked themselves together in a hexagonal structure. Several years earlier, Sir William Bragg, a Nobel Laureate for his work with x-rays and crystal structure, had deduced on theoretical grounds the hexagonal structure of ice, but it was Dr. Barnes who first showed that the theory was correct. Barnes may have been influenced in his choice of research topics by his father, a physics professor at McGill University in Montreal. It is possible, however, that Bentley’s lectures that first week in January of 1925 inspired him to push onward to solve the puzzle of the crystal structure of ice and snow crystals.

All of the quotations used in this essay were taken from Johannes Kepler’s book The Six-Cornered Snowflake: A New Year’s Gift. This book is a new translation from Latin. It was published in 2010 by Paul Dry Books.

Duncan C. Blanchard
February 2011

Bentley Work Featured at Saint Lawrence University by Wayne Howe

During these darkest days of winter Wilson Bentley’s photographs filled a gallery at Saint Lawrence University’s Brush Gallery in Canton, New York. Entitled “Marvels of the Snow Gems” it featured included original vintage microphotographs, as well as glass lantern slides dating from the era. 

Some of the photographs had never been displayed before. A small booklet of photographs had come into the hands of a Burlington resident, after being found stashed in the eaves of a house in nearby Bolton. Some of the newly found prints, as well as a items from the Jericho Historical Society, were selected and prepared for the exhibit at SLU.

The Bentley exhibit complimented a larger exhibition in the Brush Gallery. Nipirasait: Inuit Prints from Cape Dorset had recently been installed at the Canadian Embassy in Washington DC.  The powerful images can be seen in the blog found at  http://blogs.stlawu.edu/brushgallery/.

The illustration with this article is of the announcement card produced by SLU for the exhibit. It shows photos and a lantern slide on top of Bentley’s notebook. On the card SLU associate professor Aileen O’Donoghue wrote of Bentley, “ …We now explore with weather balloons, airplanes and satellites. And yet all our technology comes back to what Bentley demonstrated so well, that science- like music, art, and writing is accomplished in the details. Only with each of us attending to the details of our particular exploration and sharing what we discover there, can we continually grow in our knowledge of the world and come to recognize that we live surrounded by incredible beauty and wonder.”


Wayne Howe

Why six?by Jon Nelson

Why do so many snow crystals look about the same when rotated by 1/6 of a turn? What’s the origin of the six-fold symmetry? Why not five or seven, as Kepler asked(1)? Though we can now answer the last two questions, the first, as pondered by Bentley and many others, still awaits a complete answer.

   The origin of the crystal’s six-fold symmetry lies in its internal crystalline lattice of water molecules. Specifically, if you could zoom in about a million times into any region of a snow crystal, such as the corner in figure 1A below, you would see a lattice of hexagonal rings B) – like a microscopic internal honeycomb. The oxygen atoms (black) in each ring have the six-fold symmetry. But if you further examine the rings, notice that all of them are rotated by 30º in relation to the crystal hexagon in A). Moreover, if you look even closer, such that you can see the orientations of the molecules, and turn the ring on its side, as in C), you will see that in fact the ring is not perfectly six-fold symmetric and it’s not even flat! The honeycomb inside ice is not so simple. But if you need only a simple answer to the origin of the “6”, find it in the hexagonal lattice.


Fig. 1. Inside the surfaces of a simple hexagonal snow crystal (A). Dashed red lines in B) mark the crystal surface. The tiny arrows in C) show the same hydrogen atom in both the top view (top) and front view (bottom). Oxygen atoms are black, hydrogens are red, and lighter colors indicate further away.

   However, the simple answer has two problems. The internal honeycomb just gives us a similarity between the ice lattice and the crystal form – it suggests that the crystal may develop six-fold symmetry. But just because a crystal may have six sides doesn’t mean it will have six sides. Or, to use one of Kepler’s examples, a beehive also has an internal honeycomb structure, and yet from the outside it appears blobby and nondescript – hardly six-sided. So, just because the internal structure in snow consists of tiny hexagonal rings doesn’t mean the crystal should look the same when given a turn of 1/6. Moreover, to say that the six-sided nature comes from the hexagonal lattice just raises the next question: How did the lattice get its six-fold symmetry? It is the “Why 6” question all over again.


Fig. 2. The 4-pole tetragonal model of water. “+” and “” regions are exaggerated.

   We’ll address this latter problem first. Why is the lattice hexagonal? A common answer is that the shape of the water molecule forces the molecules to link up into 6-sided rings. Though true, it conflicts with another, little-known fact about water: depending on the water pressure and temperature, water can crystallize into, at last count, 14 other lattices, only two of which are hexagonal. That is, the water molecule’s shape does not always force the lattice into hexagons. But we happen to live under the same conditions that favor ordinary hexagonal ice, also called ice 1h (the ‘h’ standing for hexagonal), and not, for example, cubic ice (ice 1c) or tetragonal ice (ice 9). One could argue that ice 1h is the more natural form, as it requires neither very low temperatures nor any externally applied pressure. So, at least in this ‘natural’ form of ice, the shape of the water molecule produces forces that link the molecules into a lattice of hexagonal rings. 

   But what are these forces and how do they produce hexagonal rings? Bentley thought the forces were electromagnetic and in 1910 proposed an electromagnetic water model to help explain the six-sided nature of ice. The water molecule in his model(2) had two positive and two negative electrical poles plus some lesser “secondary” poles. I don’t know why he chose these numbers or where the poles were located, but his basic idea was useful. And it was far ahead of its time. In 1933, twenty-three years later, Bernal and Fowler, two pioneering ice physicists, proposed a four-pole model of water to help explain the structure of ice. But their pole model didn’t get much attention until it morphed into the more accurate “tetragonal” four-pole model in 1951. In this model, the two hydrogens are the two positive poles, and the two “lone-pair orbitals” on the other side of the oxygen are the two negative poles, as shown in figure 2. These negative poles, which are predicted by quantum mechanics, are shown as the dotted light-blue spheres. And just as Bentley had included additional secondary poles, later models added poles of weaker charge. Although we’ve known for some time that the bonds in ice are the more complex hydrogen bond, the simpler pole model here is still used to study ice because it is easier to calculate with.

   In this model, the positive pole of a molecule attracts to the negative pole of another, forming a bond; similarly, the molecule’s remaining three poles attract three other molecules. As a result, each molecule bonds to two other molecules in the ring, as shown in Fig. 3A, as well as to a neighboring ring and to a ring either above or below.

Fig. 3. Electrical forces between the hydrogens and lone-pairs (dashed blue) force the water into a hexagonal ring A) and slightly widen the opening angle of the water molecule to 106.6º (a perfect tetrahedron would have 109.5º) B). At the bottom of B), the molecule has rotated up towards us such that the angle now appears to be about 120º.

The hexagon shape occurs because the angle between the two poles on a moleculelies close to that needed for a corner of a hexagon.  In particular, this angle for a free molecule (i.e., not bound in ice or liquid) equals 104.5º (see figure 3B), which lies just 5º less than the 109.5º needed to be a corner of a hexagon. This 109.5º is less than the 120º between sides of a flat hexagon because the ring must “crumple” to form bonds to the rings above, below, and beside the ring. So the tetragonal nature of water naturally leads to a hexagonal lattice(3). As to why the water molecule is tetragonal, the answer involves the quantum electrodynamics of oxygen and hydrogen, and best left for those with much more time.

   As an aside, the tetragonal bonding leads to some curious and important properties of ice. The resulting hexagonal structure is relatively open, with large empty spaces in the rings, and for this reason ice 1h will float on liquid water. Also, as mentioned above, if we pay attention to the hydrogens, we see that the rings are not really symmetric. Moreover, the hydrogen positions have no order; notice in figure 4 below how each ring is different from its neighbors. And this lack of order leads to the curious electrical properties of ice – properties that include their being the electrical power source of thunderstorms(4).


Fig. 4. How rings link together in the hexagonal plane. Not all rings have the same water molecule orientations. Rings in the planes directly above and below line up perfectly, being linked at hydrogens or lone-pairs either directly on top (shown here) of every other oxygen or directly below (not shown).

    So the water molecule’s shape produces the microscopic hexagons, but how can this affect the surface of a crystal perhaps a million time larger? The answer involves looking at what happens where a ring contacts a crystal surface. Molecules on the surface experience unequal forces – they are pulled more towards the inside of the crystal – but these forces depend on which parts of the rings contact the surface. When only one molecule from each such hexagonal ring lies at the surface, like in the surfaces marked by red dashed lines in Fig. 5 below, the forces make that surface grow relatively slowly. And in the world of growing crystals, the slow-growing faces are the ones that spread out along the crystal, effectively erasing the other faces. It may seem strange, but for crystal faces, the fast-growers essentially burn themselves out and vanish, while the slow-growers dominate. Sometimes it pays to be slow.


Fig. 5. Why six faces, 120º apart, occur. Crystal faces #1-6 (red dashed lines) cross each surface ring at only one molecule (see arrow, face #2). If instead face #6’ formed (green dashed line), in which two molecules per ring contact the surface, then molecules A and B would soon join the face, causing #6’ to vanish and #5 and #6 to form.

   Here’s a specific example. In going around the crystal of figure 5, notice that the ring corners stick out at the surface for crystal faces #1 – 6. With only ring corners on the surface, the crystal can have neither more than six, nor less than six faces(5). Moreover, these faces all intersect at 120º corners. But if the crystal instead had a surface consisting of ring sides instead of ring corners, such as the green-dashed face #6’ instead of the red-dashed #6, then two corners would have angles of 90º and the crystal would have only five sides(6). In this case, the surface forces would be such that new molecules marked A and B would soon attach, effectively replacing face #6’ by faces #5 and 6, leaving the crystal with six sides (not including top and bottom) and six equivalent 120º corners. So this is how the microscopic internal hexagonal rings produce six, and not four, five, or seven sides of the crystal.


Fig. 6. A tiny six-sided prism grows wide and thin, sprouts branches, and maintains a remarkable degree of symmetry, allowing us to really notice its six-sided nature. Why do these things happen?

    Now, for the crystal to actually look the same when rotated by 1/6 of a turn, and be big enough for us to notice, a large, roughly symmetric six-pointed star must form. This requires three other things to happen: First, the crystal must grow thin and broad, meaning that the top and bottom faces must grow much slower than the six side faces. Second, the corners must grow outward faster than the rest of the six faces. And third, each of the six branches should grow at nearly the same rate. As to why the crystal grows so thin, this was one of the first questions Kepler asked about snow. Snow doesn’t always grow so thin; for some still unknown reason this happens only within a narrow temperature range. And how the second and third occur has some interesting aspects and mysteries(7) that will be left for discussion elsewhere. But note that whether or not a crystal is symmetric, adjacent faces differ in angle my multiples of 120º (or 60º if some faces vanish) for the reasons described here.

    In 1915, Bentley wrote(8) that he could “…hardly escape the conviction that the mysterious something that causes the crystals to grow outward only at certain points and to divide into six is electromagnetic in nature,…”. Indeed, though we’ve made many advances in our knowledge of water, at the bottom, the molecules’ electromagnetic interactions ultimately lead us to the number six – just as Bentley supposed.


1) For this and other info about Kepler, see Duncan Blanchard’s article “Johannes Kepler’s Six-Cornered Snowflakes” in this newsletter.

2) Duncan Blanchard, The Snowflake Man, McDonald & Woodward Publishing Co, Blacksburg, Virginia, 1998, pg. 147.

3) This tetragonal nature can also lead to a cubic lattice, with 4-fold symmetry, but it cannot lead to any structure with 5- or 7-fold symmetry; indeed, no crystal can have these symmetries – they are mathematically impossible.

4) See my article in the previous newsletter, “Mr Bentley’s Electric Crystals”, Snow Crystals vol 14, 2008.

5) Not always true. For example, the branched crystal in figure 6 shows 90 faces (not including top and bottom). But the most important point here is that the resulting angle between faces are always factors of 60º.

6) Actually, depending on the position of face 6’, there could be 5, 6, or 7 faces, and one or two angles could be 150º. But the argument still holds.

7) I analyze these topics in detail in my article “Branch Growth and Sidebranching in Snow Crystals” Crystal Growth & Design, vol. 5, 2005, pp 1509–1525. http://www.storyofsnow.com/media/blogs/a/Snow branching paper.pdf

8) See ref. 2, pg. 153.

News From The Gift Shop by Ray Miglionico

is proud to announce our
15th Anniversary
2011 Snowflake Bentley Collection Ornament.

We have chosen what we believe to be the quintessential snowflake design.  Simple and beautiful, one of Bentley’s most popular snow crystal photomicrograph among print collectors. Design concept drawing are below with casting set to begin in March and a release date in late April.  Once again, Danforth Pewter has created a wonderful addition to our Collection.  Made exclusively for Vermont Snowflakes.

Bentley photomicrograph used
for the design of our
2011 Ornament

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Snow Crystals Vol. #16 February 22, 2010


Editors note

Humor in the Life of Wilson Bentley by
Duncan C. Blanchard
Spanish Video Crew Reports On Bentley
by Wayne Howe
The Frosty WHIMS of Bentley
by Jon Nelson

Editors note by Peter Wolf

Well, another year has past and Bentley's Birthday was , February 7th (Recent discovery that his birthdate is the 7th, not the 9th, as previously believed) . The Jericho Historical Society celebrated Bentley's 145th Birthday on February 4th at the Old Mill in Jericho with a presentation by Mark Breen, Senior Meteorologist of the Fairbanks Museum and Planetarium, St. Johnsbury. Mark, who is the noted Vermont Public Radio (VPR) “Eye on the Sky” weather anchor-man, spoke on the vagaries and trends in past and present Vermont winters.

His illustrated presentation included remarks to celebrate the 145th birthday of  “Snowflake” Bentley (1865 – 1931), and his seminal role in the early scientific development of meteorology. A DVD copy of the presentation will be available at the Old Mill Craft Shop and on the JHS website.

This newsletter we have an article by Duncan Blanchard on the "Humor in the Life of Wilson Bentley" and an intersting  article from Jon Nelson "The Frosty WHIMS of Bentley". We also received some information from Wayne Howe on a piece in the works for Spanish Television.

We are always getting a steady stream of requests for photos for publications ranging from news and magazine articles to textbooks and holiday cards from various companies. This years publications include National Geographic, Science World, Scholastic, a display at The Smithsonian Institute and a few educational Aptitude Testing organizations have been using Bentley images.. We are still looking for teaching materials on Bentley and snow, so please share your lesson plans/units with others through the message board or email us.

As always, purchases at the Gift Shop and The Old Red Mill help preserve the legacy of Wilson "Snowflake" Bentley. Thanks to everyone who supported us this past holiday season!!!

If you would like to contribute writings to this newsletter please

Humor in the Life of Wilson Bentley
Duncan C. Blanchard

In the sixty or more articles written by Wilson Bentley, there is little indication that he had a sense of humor. But in my conversations with people who knew him, it became clear that he did indeed see humor in many of the things that happened in his everyday life, and practical jokes were part of the fun in growing up. Not only did he initiate these jokes, but some were played on him.

When very young, his delight in watching and trying to understand the ways of the birds resulted in learning how to imitate their calls. Sometimes when his mother was working in the house near an open window, he would hide outside and loudly whistle the call of a particular bird. Eventually his mother, curious to see this bird, would come out of the house only to find her young son grinning at her. On other occasions the jokes would be on visiting relatives and sometimes did not work the way Bentley hoped. A great aunt from Montana came to visit one time when Bentley had a red squirrel in a cage with a wheel for the squirrel to run on. One evening he let the squirrel out near her. The squirrel ran up the outside of her dress and bit her ear. The young Bentley got no supper that night and his great aunt returned to Montana, probably vowing never to return to Jericho again.

His niece, Alice, had fond recollections of her uncle.  “He always had some project going. He had his croquet games Sunday afternoon. There was always lots of lemonade, cookies, ice cream some days, and he had a special fudge he made from white sugar, and what they used to call vanilla drips. It was delicious. And he had evening parties when we’d hang out Japanese lanterns. One Halloween he scared everybody to death. He fixed up a large bough from a balsam tree. It was wrapped in sheets and he had a face with a florescent design, built like a skeleton. It came out of the third floor window.

Bentley liked to play tricks. Alice told me about the time a cousin came to spend the night with one of her sisters. They were to spend the night in his spare bedroom. “Well he went up there before that night. We used to have wood slats under the bed springs. He sawed then almost in two. So after they had been in bed awhile they heard snapping and cracking and wondered what that was. Pretty soon they found out. The bed went down.”

Alice told me what happened in Burlington one day when her uncle saw a big cloud over the Vermont Hotel. “He started on the run with his camera. Came out of Lapierre’s camera store. A cop took after him. He thought he stole the camera from Lapierres. Uncle said I’ll see you later, and kept running. He got the picture from the roof of the hotel and then told the cop what he was doing. He wanted that cloud before it got away from him.”

Bentley’s niece Amy told me this story. “In the springtime he loved to go out sugaring. He had a sugaring house up back. One time he was up there boiling sap well into the night. He came back and all my brothers and sisters were around. He said he was working up there and suddenly saw these two bright eyes staring into the darkness. He said they were the eyes of lynx. We were horrified. All we could think of were these animals up there, the lynx. Uncle said ‘Yes, two big eyes. They were made of links of chain.”

Sometime in 1917 photographers from Pathe News showed up in Jericho to make a short movie of Bentley taking photomicrographs of snow crystals. They had him wear his best dress-up clothes: white shirt and collar, black tie, dark overcoat and a soft felt hat. Bentley must have fussed and fumed over this, as he never worked out of doors with his camera, and he certainly never dressed up when he did his photography. Since the thin broom splint he used to transfer a snow crystal from his blackboard to a microscope slide would never show up in the movie, the photographers had him use a tapered piece of wood over a foot long and as thick as a pencil. This only served to increase his irritation. But it must have reached record levels when the photographers decided it would be nice to have snow falling while their cameras were rolling. But it wasn’t snowing that day, though there was snow on the ground. No problem. What passed as the special effects team of Pathe News leapt into action. They scooped some snow from the ground into a basket and had Bentley’s nephew take it to a second floor bedroom where he tossed handfuls of it into the air from an open window.

It was a disaster. Instead of having soft white snowflakes descend slowly and uniformly over Bentley, large chunks of snow fell like hailstones, some striking his hat, others his shoulders, producing splashes of snow that dotted his hat and coat with white smears. No matter. Snow was snow. The movie camera kept rolling and captured Bentley in his element.

The movie runs only a few minutes in length, but it is the only known motion picture of Bentley in action. The still photographs taken that day would be used many times by Bentley and others, and are still being used today.

On quiet evenings Bentley often took his clarinet up on the hill behind the farmhouse and play for his own entertainment. But the neighbors below were entertained too, as they heard the soft notes of the music drifting down from above. Sometimes Bentley would play from his own porch. Alice said you could hear it all over Nashville. He’d play all kinds of music. Not only did Bentley entertain people from his porch and hillside with his clarinet, but at an evening’s gathering at the schoolhouse he would with his violin and sense of humor imitate birdcalls, frogs, barnyard animals, and certain people in the village!

During the long, cold winter evenings the people of the Nashville section of Jericho entertained themselves with square dances. Sometimes they would gather at the Bentley home, other times at one of the neighboring farmhouses. Whether the dances were held at the Bentley home or elsewhere, it was always Bentley who did most of the piano playing. Arthur Pratt, a young Bentley neighbor, told me an incredible story of what happened one night when the dance was being held at a neighbor’s house. He and a few other boys quietly left the house and went outside to where Bentley had left his horse and buggy. They had decided to play a trick on him. Quickly they reversed the wheels on the buggy, so that the larger rear wheels were on front while the smaller front wheels were on the back. This gave a strange and lopsided appearance to the buggy. Pratt and his friends hid in some bushes to eagerly await Bentley’s reaction when he came out and saw what had happened. And what was his reaction? There wasn’t any! “He went home like that,” said Pratt in amazement,  “and drove that buggy several days before he noticed it. I don’t know what you call that.” One might call it absentmindedness or one might just call it an example of Bentley’s mischievous humor.

When I told this story to Alice, she said “I remember that because I rode with him out to Jericho Center with the big wheels still in front. He went out to the Jericho Center village store, but he didn’t let on; course he knew about it the night he came home. He let them know it didn’t bother him at all.”

Alice asked her uncle why he was being so different from all the others in driving his buggy that way. He told her there was nothing wrong in being different from other people. That was a lesson in courage a little girl never forgot.

Being different, however, sometimes caused interesting and amusing clashes with the law. Take the time that Bentley, who in addition to his interest in the water wonders of the atmosphere was also an avid amateur geologist, was down along the river in Richmond collecting stones. He picked some up, inspected them, tossed most back, but kept a few interesting specimens to take back home. “There was a young woman living alone,” Amy told me, “She saw him down there wandering around. She got nervous. His actions were peculiar, so she called the sheriff and told him that this man was acting kind of funny. So the sheriff, Mike Murphy, came down, saw uncle, and said, ‘Humph, I might have known it was you.’”

My last example probably was humorous to most people but to Bentley it was a source of joy and delight. In April 1926 he was on a lecture tour that took him to several cities, including Philadelphia and New York City. He wrote an account of the trip in the Burlington Free Press. In New York he visited the Metropolitan Museum of Art. As he wandered down the halls, he gazed at both ancient and modern statues, admired the gem stones, and nodded approvingly at many of the paintings, especially those of landscapes. But he had nothing good to say about what he saw in the “portrait section,” and let his readers know exactly what was wrong.

“I looked in vain for one really pretty face there. It seems such a pity, with all the wealth of material at hand in America, that the rare beauty and glory of the American girl has not been reproduced on canvas by some master painter’s hand. If art, or that part of art reproducing portraits, concerns itself only with the commonplace, the homely and the ugly, then I have no great admiration for this part of art. “

As if to refute what he had seen in the portrait paintings, Bentley walked along Broadway near Times Square, and stood in Grand Central Station where he saw many faces:

“. . . of rare beauty. I think many Vermonters know of the writer’s interest in smiles from the viewpoint of art and beauty. On my trip I found many girls possessing charming smiles. When complimented and questioned if they knew why they smiled prettily, the lucky possessors answer was invariably ‘no.’ So it seems hardly anyone knows the why and wherefore of a pretty smile. “

                    Duncan C. Blanchard
                    February 2010


Spanish Video Crew Reports On Bentley
by Wayne Howe

Bentley's story continues to draw interest from all over. In December a film crew working for Radio Television Espanola came to the Old Red Mill to tell the story of Bentley's work to the Spanish speaking world. The two person crew filmed the objects in the gallery and interviewed Wayne Howe about Bentley's life and work. The interviewers were interested in how other people in town viewed Bentley. The piece is scheduled to be show in Spain sometime in the next few months.

The documentary film maker who conducted the interview was Guillermo Fesser. Formally of Madrid and now living in the US, he writes and reports stories for Spanish television and radio. Mr. Fesser's goal is to broaden the Spanish people's understanding of the United States.

As Spaniards may not fully understand how large and complex a country is, Vermonters may not appreciate that Spain is more than sunny and warm

fishing villages and cattle farms. Spain has snow! There are a number of ski areas and winter storms can play havoc on the best made plans. Photos from Madrid this past January depicted snow laden cars. One passerby scrawled NIEVE (snow) on a windshield with their finger.   

The interviewers drove six hours from their homes on the Hudson south of Albany, NY. Armed with a small digital camera they did not need lights or heavy equipment. This is in marked contrast to film crew of years gone by. Everything is getting smaller, except apparently, interest in Snowflake Bentley.

The Frosty WHIMS of Bentley
by Jon Nelson

The most comprehensive study of frost and small ice formations was published way back in 1907 by Wilson A. Bentley. His article was split into five successive issues of the Monthly Weather Review [1] with the title “Studies of Frost and Ice Crystals”. In the article, Bentley details his classification system for frost and some related ice forms, and gives examples of nearly every type – in total 274 examples in photographs. His classification system is ingenious, the first (and probably only) classification system for frost and ice on surfaces. Unfortunately for such an extensive, pioneering article, few books or articles cite it as a reference.

Bentley’s classification system gave each crystal form a 3-letter label. The first letter gave the type of frost or place of deposition. He designated five such types: window-frost (W), hoarfrost (H), window-ice (I), massive ice (M), and hailstones (S). Considering the first letter of each type, we could call this the WHIMS system. Briefly, “W” includes curvy frost that forms within a relatively thick condensation film on surfaces (in his studies, windowpanes), “H” includes the long, densely packed, straight needles sticking out of exposed surfaces on cold mornings outside, “I” is ice that forms on relatively dry surfaces, “M” is ice that forms in “thick” bodies of water like puddles and lakes, and “S” is hailstones.

The second letter designated the characteristic form of the crystal. In all, he designated 20 types, but some letters were used for several forms. For example, although “B” would designate only a branch-like form, “C” could designate either column-like or coral-like forms. So, presumably, “WC” could mean either window-frost crystals in a column form or window-frost crystals in a coral form. “T” is similar in that it stands for either tabular or tooth-like forms. However, of the crystal types classified by Bentley, there was little confusion because W-types had only one C-characteristic, and that was WCG, or window-frost resembling columns. The other C-characteristic occurred only in massive ice, specifically MCF, massive ice resembling coral. Even if there had been two WC types, they would be distinguished by their third letter, the letter that designated how common the form appeared (at least to him). Specifically, an “A” would indicate that this is the most common form, a “B” would be less common. In principle, this could continue until “Z”, though the ones he classified only went as far as “K”. For example, in the most-used letter “F”, we distinguish two WF forms because one is WFC, a filament-like form that is relatively common, and WFJ, a fiber-like form that was rare. The other two Fs refer to filament-like and flower-like forms.

Bentley’s WHIMS system is extensive and well-thought out, but it doesn’t include frost of two origins. In particular, film-frost on non-glass surfaces is common, but very hard to see unless some white hoar crystals grow up and off the surface. In addition to revealing the pattern of film-frost, the hoar that grows up off the frozen film can have it’s own characteristics. This case is hard to fit with Bentley’s classification, yet I see it far more often than pure film-frost. He was aware of this case, as he mentions such dual types in his discussion of the stages of window-ice formation; specifically, he divides their growth into four stages with the fourth stage being hoarfrost. This difficulty is related to another shortcoming: it is not clear what exact purpose he meant for the second letter. He wrote that this letter represents the characteristic form, and for hoar, he clearly refers to characteristics of the crystals, labeling them either columnar (C) or tabular (T). But with window-frost and window-ice, it is often hard to distinguish the individual crystals, and the characteristic pattern one sees are partly, sometimes wholly, a consequence of the positions of the crystals, not their individual shapes.

Judging by the number of examples, the type he enjoyed the most was type IFA, featherform window-ice crystals. As this type includes a wide range of patterns, it’s too bad he didn’t create IFB, C, D, etc. to distinguish some of the patterns. These patterns include my favorite formation, which I nicknamed “striped tail frost”. He called them “the most strange and rare specimens of beautiful feather-form window-ice crystals”. He likened their pattern to an evergreen vine, and gave some description of the special conditions that produced them. For the images he showed, he explained a mechanism in which the windowpane cooled from the right edge to the left edge, and because of sunshine and “zero weather”, the temperature change was large. Below I show a similar frost formation, except the frost is on the roof of a black car, not a windowpane.

A close up of three bands of the tail, shown below, suggests that the pattern consists of many thin, slightly curving ice blades. But the magnification from my compact camera does not reveal a clear reason for the alternating dark and light bands.

In other formations, I’ve noticed that the whiter parts are hoar crystals that either stick up much higher than other regions or are denser [2]. Bentley offered the former reason for the white bands. But it almost appears that the white parts are where new blades start, to fill in the gap left by two existing blades that diverge. If this is the case, then the white bands are places where the hoar is denser. If I see this pattern again, I’ll try to get a clearer close-up image to help determine the origin of the white bands.

Bentley’s article should be read by everyone who wants to learn about frost. It is easy to read and contains a lot of careful observations, including high magnifications of frost features, and many good ideas. For example, Bentley argued that all columnar hoarfrost probably starts after small condensation droplets on a surface freezes. After observing a lot of hoarfrost over the past few years, I came to the same idea (though I suspect it applies to tabular hoar as well). Unfortunately, another one of his statements did not stand the test of time very well:

"It is a delight to know that our windowpanes will for all time be glorified and beautified in winter by these exquisite creations of window ice, and by those other elegant crystal structures that are next of kin to them, the window-frost crystals."

Even though few windowpanes these days get cold enough to frost, many outdoor surfaces do, and these show the same patterns Bentley classified as well as some new patterns. And although his WHIMS system has seen little-to-no use, it may have inspired a similar classification system that cloud scientists now use for snow crystals. The snow system, begun by Ukichiro Nakaya, a scientist inspired by Bentley, wasn’t published until nearly 50 years had passed [3]. Twelve years later, Nakaya’s system was extended to the Magono and Lee version used today [4]. But Bentley’s system is open-ended; that is, one can keep adding rarer and rarer forms to it. So in principle, his system never needs to be extended [5]. It seems once again that Bentley was way ahead of the pack.

[1] This article is freely available on the internet. The five parts are at the links below. All 274 images are at link e).

a) http://docs.lib.noaa.gov/rescue/mwr/035/mwr-035-08-0348.pdf
b) http://docs.lib.noaa.gov/rescue/mwr/035/mwr-035-09-0397b.pdf
c) http://docs.lib.noaa.gov/rescue/mwr/035/mwr-035-10-0439.pdf
d) http://docs.lib.noaa.gov/rescue/mwr/035/mwr-035-11-0512b.pdf
e) http://docs.lib.noaa.gov/rescue/mwr/035/mwr-035-12-0584.pdf
[2] See some of the images on my blog at http://www.storyofsnow.com/blog1.php
[3] Nakaya, U. (1954) Snow Crystals: Natural and Artificial (Harvard University Press)
[4] Magono, C. and Lee, C. (1966) Meteorological Classification of Natural Snow Crystals. J. Faculty of Science, Hokkaido University. Series 7, Geophysics 2(4) pp. 321- 335. Also, see this classification in Edward R. Chapelle’s nice little book “A Field Guide to Snow Crystals”. It is probably also in Kenneth Libbrecht’s “Field Guide to Snowflakes”.
[5] But it could be revised. On a somewhat whimsical note, I suggest the BEDFISH revision on my Jan. 31st posting at reference [2].

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Snow Crystals Vol. #15 March 23, 2009


Editors note

Bentley’s Struggle to Photograph Snow Crystals by
Duncan C. Blanchard
World Famous Photographers Tip Hat to Bentley by Wayne Howe
The Bentley length scale and snow crystal variety
by Jon Nelson
News From The Gift Shop
by Ray Miglionico

Editors note by Peter Wolf

Well, another year has past and Bentley's Birthday was , February 7th (Recent discovery that his birthdate is the 7th, not the 9th, as previously believed) . Emilie Alexander fills us in about the birthday celebration at the Jericho Town Library, which  rang in One-hundred forty-four years ago that Wilson Bentley was born on the Jericho farm where he lived his entire life. We continue our Jericho Center Weather conditions which are updated to a web page every 15 minutes and historical weather data charts are also viewable.  Bentley would record the weather conditions in a notebook throughout the day, each day, his whole life. Our current weather station records data automatically and I wonder if Bentley would rely on the new technology or the "old school" ways of manually recording the data?.

Ray Miglionico from Vermont Snowflakes recently acquired some new photos by Bentley that we have never seen before and we present some for the first time here.

We have an article by Duncan Blanchard  "Bentley’s Struggle to Photograph Snow Crystals", and a mind bending article from Jon Nelson "The Bentley length scale and snow crystal variety". We also received some information from Wayne Howe on an exhibit at the Middlebury College Museum of Art in Middlebury, Vermont

We are always getting a steady stream of requests for photos for publications ranging from news and magazine articles to textbooks and holiday cards from various companies. This years publications include Yankee Magazine, Inc Magazine, The N.Y. Post, The Old Farmers Almanac and Ranger Rick. We are still looking for teaching materials on Bentley and snow, so please share your lesson plans/units with others through the message board or email us.

As always, purchases at the Gift Shop and The Old Red Mill help preserve the legacy of Wilson "Snowflake" Bentley. Thanks to everyone who supported us this past holiday season!!!

If you would like to contribute writings to this newsletter please

Emilie Alexander

Refrains of Happy Birthday Snowflake Bentley rang form the rafters of the Jericho Town Library at the annual Jericho celebration of the birth of our noted citizen Wilson Bentley.  He would have been 144 years old this February 7.  ( I know there is a discrepancy in the date but the birth certificate in the Jericho Town Hall says February 7  not  9).   Many children and adults gathered to hear about the life of Bentley as narrated by Elaine Salsbury of the Jericho Historical Society, see slides of his life and snowflakes.   Snowflake Bentley (portrayed by Devon Mendicino) appeared and shared some of his more unusual snowflakes with the crowd. 

Snowflake crafts were enjoyed by the younger set and birthday cake donated by Grace Mobbs from Cakes by Grace was enjoyed by all.  Bentely would have been pleased to see that the town thinks a great deal of his work and marvels today at this expertise and the beauty of the individual flake.

Thanks to the Jericho Town Library for celebrating  Bentley's B-day. 

Bentley’s Struggle to Photograph Snow Crystals
Duncan C. Blanchard

At about age fourteen, Wilson Bentley’s interest and curiosity about the world of nature had so overwhelmed him that he no longer was interested only in reading about it in books. He had to see this world for himself. On his fifteenth birthday on February 7, 1885, he received the gift of an old microscope that had been used by his mother during her school-teaching days. From that time on, he was not the same. He had found a focus in life. He became obsessed with the fragile beauty of common things from the world around him as seen through the microscope, especially the delicate   beauty of the snow crystals. Years later, Bentley had this to say about the beginning of this life-long obsession.

 “When the other boys of my age were playing with popguns and slingshots, I was absorbed in studying things under this microscope: drops of water, tiny fragments of stone a feather from a bird’s wing. But always, from the very beginning, it was the snowflakes that fascinated me most. . . . Under the microscope I found that snowflakes were miracles of beauty, and it seemed a shame that this beauty should not be seen and appreciated by others. I became possessed with a great desire to show people something of this wonderful loveliness, an ambition to become, in some measure, its preserver.”

But how do you preserve this beauty and show it to others? He took the microscope to an unheated woodshed attached to the back of the house. There he spent countless hours peering through his microscope at snow crystals on a microscope slide.

As if Bentley did not have enough difficulty finding a snow crystal and getting this tiny sliver of ice safely under the microscope, he had to be extremely careful not to breathe out in the direction of the crystal; otherwise it would melt instantly before his eyes. Holding his breath while looking through the microscope, he tried to sketch on a piece of paper exactly what his eyes were seeing. When he could hold his breath no longer, he turned his head away, rapidly exhaled, gulped in another lungful of cold air, and returned to his drawing. This went on for snow crystal after snow crystal, all different, and for storm after storm, not for one but for three years.

By this time, he had about four hundred drawings, but he still had problems. Even though he was willing to sit there in the bone-chilling temperatures of the woodshed and patiently continue to draw, nature placed a severe limit on the time he had to work. Snow crystals are made of ice, and water molecules evaporate or sublimate from ice, even at temperatures far below thirty-two degrees Fahrenheit, though at a much slower rate than they do from liquid water at a far higher temperature. Another problem facing Bentley was that the evaporation does not occur at the same rate from all places on the crystal. It occurs much more rapidly from the tips or sharp edges to flatten or smooth it and thus distort the crystal as it shrinks in size. Bentley probably had less than five minutes to get the drawings done. Anyone who has seen the beautiful but complex structure of snow crystals knows that even fifty minutes would not be enough to draw them. Faced with this problem, Bentley knew he would never be able to capture these “miracles of beauty” in his drawings. Somehow, somewhere, he would have to find another way.

Increasingly frustrated in making drawings of snow crystals seen under the microscope, his thoughts turned to photography. He wondered if it would be possible to use what was then a relatively new technology barely out of its infancy, and adapt it to make photographs of snow crystals. Before 1880 wet plate photography was commonly used. But in the late 1870s dry plate photography was developed in England, and by the early 1880s was available in America. Dry plates, unlike wet plates, could be exposed, put aside, and developed days or weeks later. This new, easier method of photography arrived just in time for Wilson Bentley.

In the early 1880s, cameras were still a novelty and not used by the average person, much less by farmers’ sons in the Mill Brook Valley of Jericho. Indeed, George Eastman, who was later to revolutionize photography by making his Kodak cameras easily available to amateurs, was just then inventing the flexible paper films which were used for the next 80 to 100 years. So who or what gave Bentley the idea it might be possible to use  photomicrography to capture on photographic plates all the intricate details of a snow crystal? Perhaps he read about it in a magazine or book, or maybe an older person, a friend of the family knowledgeable in photography, told him about it and helped him get started. Bentley, in his many articles published years later, never mentioned anyone helping him in his early struggles with photography, but there is one person who may have been influential.

Henry Seeley, about twenty years older than Bentley, was born in the valley not far from the Bentley farm. He served in the Civil War, and in 1872 opened a photographic studio in Bridgeport, Connecticut. During frequent visits to Jericho, he often talked to Bentley about photography. After Bentley’s death, Seeley said:

“He was a genius, known the world over. No question about that. … I got him his first camera, and showed him the making of plates, and whenever there was a new book published on photography I used to send it to him, but it was not many years before he could send me information. “

Seeley does not mention a microscope or photomicrography, so the camera he got for Bentley may have been a small one for photographing scenes around the valley a year or two before Bentley decided to try photomicrography. Nevertheless, even if Seeley was not directly involved in Bentley’s pioneering experiments in the photomicrography of snow crystals, it seems clear that he introduced Bentley to photography. This was all Bentley needed to go where no one had gone before in the photography of the natural world.

Bentley probably read all he could find on photography, especially photomicrography, and concluded he could progress no further in his quest until he had the proper kind of microscope and a camera. But where would he get the money to buy such technical equipment? He was still a teenager. Besides, his regular chores on the farm left him with little time to work elsewhere to earn the money he needed. It was his mother who convinced a reluctant father that they just had to find the money that young Wilson needed. Years later, Bentley told what happened.

“When I was seventeen years old, my mother persuaded my father to buy for me the camera and microscope which I developed into the apparatus I am still using. It cost, even then, one hundred dollars! You can imagine, or perhaps you cannot, unless you know what the average farmer is like, how my father hated to spend all that money on what seemed to him a boy’s ridiculous whim.

“Somehow my mother got him to spend the money, but he never came to believe it had been worthwhile. He and my elder brother always thought I was fooling away my time, fussing with snowflakes.”

When the camera and microscope arrived, Bentley must have spent many weeks experimenting, trying different ways to connect them together and to rapidly focus on the ground glass screen at the rear of the camera whatever was on the stage of the microscope. His new compound microscope was the lowest-priced model of about ten made by the Bausch and Lomb Optical Company. It came with a three-quarter inch focal length objective of wide aperture.  “Because of its simplicity,” the Bausch and Lomb catalog said, “It may be used by inexperienced hands without detriment or injury to it.” The bellows camera, about seven inches square, could be extended nearly three feet. At the back was provision for focusing on a ground or clear glass screen and for the attachment of a photographic plate holder.

But before he could do any experimentation with his new microscope and camera, he had to have something to place them upon. He obtained a wood table about three feet high, a bit over two feet in length, and slightly more than a foot wide. The carpentry skills displayed by the use of screws rather than nails in the table, were in marked contrast to the jury-rigged frame that was built and placed on the table to hold the camera and microscope. The wooden frame, held together only by nails, had the appearance of being slapped together hastily in order to get on with the experiment. This suggests that Bentley had obtained the table elsewhere and had himself made the frame which, though crude and by no means elegant, served his purposes admirably for over fifty years. In this and in other things, Bentley showed that he believed in that old bit of Yankee philosophy: “If it ain’t broke, don’t fix it.”

The camera took up so much room on the table that, in order to accommodate the microscope, Bentley had to make the frame long enough to stick out about a foot beyond the end of the table. He placed the microscope on the frame extension and bent the upper part backwards ninety degrees around a hinged joint. He removed both the eyepiece of the microscope and the lens of the camera, then pushed the microscope toward the camera until the tube or main body had seated itself in a light-tight sleeve attached to the front of the camera. He next used either the fine or coarse focusing knob to get a sharp, magnified image on the camera’s ground-glass screen of whatever was in front on the microscope stage.

For many people, the focusing would have posed no problem, but for Bentley, slight of build and with short arms, it was nearly insurmountable. Standing at the back of the camera under a large black cloth to keep out stray light, he strained to reach the focusing knob to sharpen the fuzzy image he saw on the ground-glass screen. He could not reach it, so he had to take a few steps to the front of the camera to make a slight focusing adjustment. Often he had to repeat this, and soon realized that when he worked with a snow crystal, he would have to move much more rapidly. But how would he do it?

He did this in a very clever way. He had noticed that when the microscope was in its bent-back position, the axis of rotation of the fine-focus knob was horizontal, parallel to, and below the optical axis of the microscope. On  both sides of the frame he attached vertically a short piece of wood with a  metal eyelet atop each piece. Near the back of the camera and on both sides of the frame he attached a wooden wheel. He next took a long piece of string and wound it a couple times around the focusing knob, then led it through both eyelets and back to the wooden wheels where he attached it. With this arrangement Bentley could look at the fuzzy image on the ground-glass plate, and turn the wooden wheels until the focusing knob brought the image on the plate into a sharp focus. The beauty of this was that he could do it in just a few seconds.

But how do you get a snow crystal on the glass slide in front of the microscope? Bentley had solved this problem during the long months of earlier winters when he tried to draw the crystals he saw under his microscope. He collected the crystals on a small black board. Standing outside the woodshed, he watched the snowflakes and crystals falling on the board and occasionally looked at them with a magnifying glass. If he did not see one he wanted to photograph, he would brush the snow off with a turkey feather and start anew. When he found a crystal he wanted to photograph, he would rush inside the woodshed to transfer it to a microscope slide.

Here began the most delicate part of the whole process. Using a broom splint from one of his mother’s brooms, he gently touched it to the middle of the snow crystal, picked it up and placed it in the center of the microscope slide. He needed a steady hand to do this. Some of the crystals were only a sixteenth of an inch in diameter. Commenting on this in later years, Bentley said, “My hand is perfectly steady. . . .  have never used liquor, tobacco, or any other stimulants that affect the nerves.”

The delicate part of the process over, Bentley began a race against time. Quickly he placed the slide under an observation microscope to make sure the snow crystal was unbroken. If it was, he placed the slide on the microscope stage and hastened to the back of the camera. He rapidly obtained a focus on the ground glass, removed it, replaced it with a photographic plate and exposed it to the magnified image of the snow crystal for anywhere from about thirty to three hundred seconds. For light he simply pointed his camera toward a window in the side of the woodshed and allowed the light to pass through the snow crystal on its way to the photographic plate. Using this technique of transmitted light, Bentley expected his photomicrographs to show not only the surface but the internal structure of the snow crystal. Since he had no use for the camera lens and had removed it, he had no shutter to open and close for the proper exposure time. He made his own shutter with a small black card mounted in front of the objective. He removed the card for the required exposure time, then replaced it. The plate was then ready for developing.

Bentley probably completed the camera-microscope assembly in †he late fall of 1883 and eagerly looked forward to the first snows of winter. Did he obtain instant success in his quest to capture the image of a snow crystal? He did not. He struggled for weeks on end with the apparatus but nothing seemed to work.

“Here I was with this expensive apparatus which had been given to me so reluctantly. I had been sure I could do wonderful things with it, but I failed over and over again! . . . If there had only been someone to explain what was wrong! But away off here on a farm there was nobody to help me. Again and again I failed. The winter slipped away, and I was almost heartbroken. But by the next season I had found the secret of my trouble. I began to use a very small ‘stop’--- a thin plate, with a tiny opening to shut out most of the light. With this and a longer exposure, I got a clear image. . . .”

The “tiny opening “ was probably the smallest of four medium-sized holes in a metal disc mounted just beneath the microscope stage. The disc --- a revolving diaphragm --- could be rotated to bring any of the holes directly beneath the stage and thus control the amount of light passing through the snow crystal and the microscope. The smallest hole had a diameter about one sixteenth of an inch, the largest was five-eights of an inch. It appears that during that first winter Bentley used the largest opening in an attempt to get a lot of light rapidly onto his film and thus lowering the time required to get the picture. This was fatal. With a large opening, the depth of field was very small, and it was extremely difficult to get a sharp focus. When he finally used the smallest opening on the disc, the resultant increase in the depth of field made it possible to quickly obtain a sharp, crisp focus. A longer exposure was now necessary, but it gave the “clear image” he was seeking.

Bentley later said: “The day I developed the first negative made by this method, and found it good, I felt almost like falling on my knees beside that apparatus and worshipping it! I knew then that what I had dreamed of doing was possible. It was the greatest moment of my life.”

This was on January 15, 1885. It was a dark, overcast day during which about five inches of snow fell outside the woodshed. With eager anticipation Bentley probably developed the first of five negatives taken that day, long before he had to turn his attention to the evening chores. Though he did not know it, Bentley’s success that day in the woodshed had produced the world’s first photomicrographs of snow crystals. He was still only nineteen years old!

From that moment on, his magnificent obsession with the snow crystals never waned, and he faithfully returned to his studies every winter of the forty-six that remained in his life.

On Sunday, March 1, 1931, a “lovely day” as Bentley described it,  with an early morning temperature of twelve degrees rising to thirty-four later in the day, he photographed a single snow crystal. That brought his total collection of photographs to 5,381! There would be no more. After forty-seven successive winters of snow crystal photography, he had taken his last picture. His old battered camera would never be used again.

World Famous Photographers Tip Hat to Bentley
Wayne Howe

Doug and Mike Starn are known for their manipulations of technique and materials that create arresting photographs. A small exhibit of their work can be seen through April 19th at the Middlebury College Museum of Art in Middlebury, Vermont. The museum recently acquired photomicrographs of snowflakes, and other works of these well regarded photographers.

The identical twin brothers first began photographing objects at age thirteen. Now, at 48, the brothers’ work is exhibited throughout the world including the Metropolitan Museum of Art and the Whitney in New York, The Los Angeles County Museum of Art, the Art Institute of Chicago and the High Museum in Atlanta. Overseas exhibits include Sweden, Britain, the Netherlands and Korea. The exhibit at Middlebury includes snowflakes, as well as works depicting trees similar to an installation being completed for New York’s South Ferry subway terminal.

At the entry to the gallery room stands a large print that combined inkjet with varnish and acrylic paint, and measures almost four feet by five. The blend of photography, handmade materials and varnish gave the image an extra dimension. A gun metal blue cast gave the edges of the snowflake a hard and cold edge. In a tip of the hat to Bentley, Emmie Danadio, curator of the exhibit wrote, “The tree and the snowflake images in view are defining subjects for the Starns. This body of work was conceived in Vermont, where the pioneering excursions in photographic microscopy by Wilson Snowflake Bentley (1865-1931) first demonstrated that no two snowflakes are alike. “  

A larger work on display is composed of 24 snowflake images. The installation has a sixties modernist ascetic. The images were reproduced using inkjets and then sandwiched between lightweight aluminum and Plexiglas using liquid glue. The snowflakes are all of the same type: delicate lacy dendrite forms characteristic of high humidity. The grid of photos brought to mind a page from Bentley’s book. However, they differed in that they were all of one type and none of the flakes were whole. They all look damaged. None of these photographs would have been retained by Bentley. Produced during snowstorms over the course of three winters in Jay, Vermont, Doug and Mike Starn must have been mindful of the challenges Bentley faced in his work. 

Bentley’s appreciation for both the science and beauty of snowflakes is found here, though his works are absent.  A bit of text on the wall of the gallery captures a common spirit. Doug and Mike Starn found snowflakes, “transient, unique and instantly recognizable.” Bentley recorded similar sentiments.

For more information on this exhibit go to http://museum.middlebury.edu/exhibitions

Wayne Howe
12 February 2009

The Bentley length scale and snow crystal variety
by Jon Nelson

“… by means of these wonderfully delicate and exquisite figures, much may be learned of the history of each crystal and the changes through which  it has passed in its journey through cloudland.”

                                                                                                      W. A. Bentley, 1898

“… the crystals will in all probability be greatly modified by passing through atmospheric strata varying so greatly in density, temperature, humidity, etc. That they are greatly modified by these flights in the cloud is clearly shown by the interior structure of many of the crystals. ”

                                                                                                      W. A. Bentley, 1901

Bentley claimed that the various layers (‘strata’) of air that a snow crystal falls through largely determine the appearance of the crystal. The first direct support of this claim came about 30 years later, from laboratory experiments by Ukichiro Nakaya, a Japanese physicist. Now, 100 years later, probably all cloud scientists would agree with Bentley. So, with all the crystal and cloud research that has been done since Bentley and Nakaya, can we determine the history of a crystal if we see its form?  Can we finally do what Bentley said we should be able to do?

    Hardly. Laboratory experiments have certainly advanced our knowledge of snow, though large, crucial gaps remain and many experiments appear to contradict other experiments. Greater advances have occurred with cloud measurements. For example, researchers recently measured differences in temperature between points less than one centimeter apart in clouds. (Which is not so easy when one is flying at over a hundred meters per second!) Nearly the same sensitivity measurements have been made of cloud humidities and air motions. Although I was not involved in any of these cloud measurements, the researchers gave me data that I used to estimate the size of the layers that Bentley mentioned. Now, knowing the size of the layers does not allow us to know the exact history of a crystal, but it does help us understand something else dear to Bentley: the wonderful variety of snow crystal forms. As far as I know, nobody else has estimated this size, so I took the liberty of naming it the ‘Bentley length’.

   Before describing what this length is, I should clarify two things. One, the length is not fixed: it depends on the cloud conditions, particularly the temperature. Two, these ‘layers’ are not something one can easily discern by looking at a patch of cloud: the size of a layer depends not only on the properties of the cloud, but also on how fast the crystal can respond to changes in the cloud, particularly temperature changes. Specifically, the length is the average distance a crystal falls through the cloudy air before some fluctuation in air temperature or humidity causes the crystal to make a noticeable change in shape. About this change of shape, one of Nakaya’s great achievements was to demonstrate that snow crystal shape and size is remarkably sensitive to temperature: grow a snow crystal at –11 °C for 30 minutes and it ends up less than half a millimeter across, but grow it at –15 °C, only 4 degrees colder, for the same length of time and the crystal is more than 5 mm across. Using similar data on snow crystals and the above-mentioned data on clouds, I estimated that the Bentley length is about 8 meters at –11 °C, and only 0.8 meters at –15 °C. To a snow crystal, even four degrees is a huge change.

    To understand the role of the Bentley length in snow crystal variety, it helps to look into all sources of crystal variety. First, consider an analogy. The uniqueness of snow is sometimes compared to the uniqueness of individuals. That we are all unique is well known to be a result of our genes and our environment. Even identical twins who grow up in the same general environment will, despite having the same genes, develop differently due to small differences in their environment. The genes do not determine the person, but rather determine how the development of the person responds to the environment. Similarly, the structure of the initial embryo of ice, the seed that starts a snow crystal, influences how the crystal will respond to the cloudy environment. Concerning the environment, we can divide the crystal environment into that which would occur if all cloud fluctuations were removed, and the small differences in environment caused by the fluctuations. For example, consider a crystal that starts at –15 °C the middle of a cloud that everywhere has an updraft speed of 12 cm/s. At first the crystal slowly cools as it rises. But soon it reaches a size at which it falls faster than the updraft and from then on, the crystal slowly, and continuously, warms as it descends towards cloud base at –8 °C.  This history would produce a crystal that may look something like that on the left in the illustration below. Conversely, the crystal would look different if it started at –16 °C or some other temperature. But real clouds have fluctuations in the updraft speed, fluctuations in temperature, and fluctuations in other things. These fluctuations also affect the crystal form, just as the small differences in environment affected the twins. One such fluctuation on the right side of the illustration led to a slightly different crystal. So, that which is unique to a given crystal can be said to have originated from a combination of three sources. The third source, the fluctuations, depends on the Bentley length.

   To recap, two crystals could be different because they started with different characteristics that affected their final appearance. That’s the first source. The two crystals could instead be different because they started at different temperatures or grew in different clouds. Or, as the third source, the two crystals could have passed through different cloud layers. Bentley also discussed these three sources. He originally assumed that the first one was negligible:

Of the tens of thousands now filling the air, an infinitesimal proportion fall on this board; nor is there any good reason to doubt that when they started from equal heights on their journey earthward, many of the snow crystals were exactly alike in shape, and size, and probably in density.

But later, through a “fortunate accident” involving a broken water pipe that flooded a cold room in his house, he decided that crystals are also born with individual characteristics that can affect their appearance.

   Even with our incomplete knowledge of snow-crystal growth, it is possible to estimate the crystal variety resulting from these sources. Here I define ‘variety’ to mean the number of possible distinguishable crystals that could result from crystals falling through the layers. According to the data, the third source of variety greatly exceeds the second, and the second source greatly exceeds the first. So, the atmospheric ‘layers’, the third source, is likely the main source of crystal individuality. And if one would like to estimate the crystal variety for some set of conditions, one needs to know how many layers a crystal passes through. Here is where we use the Bentley length.

   To see just how much the Bentley-length source dominates snow crystal variety, we apply a little mathematics to the example in the illustration. According to experiments on ice-crystal growth rates and fall speeds, by the time the crystal falls below cloudbase, it would have fallen through about 1850 meters of air and grown to about 7.6 millimeters across. (Yes, this is a big crystal.)  

    With a Bentley length of 0.8 meters, which is appropriate for the crystal’s starting temperature, the number of layers the crystal passed through would be the 1850 meters divided by the 0.8-meter length, and assuming that half of the layers produced changes to the crystal, the crystal experienced 1156 changes. One example of a change is shown in the illustration. However, the Bentley length depends on temperature, and by the time the crystal gets to cloud base, the length is more than four times larger. If we instead use the average Bentley length for the crystal’s journey, the crystal experienced 468 changes. This might seem like a small number, but we have not yet calculated the variety.

    When the crystal passed through a given layer, the growth could have sped up or it could have slowed down. In the case of the illustration, the colder region caused the growth to speed up, and this produced the narrower tip and sidebranches. If instead, the fluctuation had been a region of warmer air, the growth would have slowed and the crystal tip would have widened. However, the Bentley length tells us only how many changes occurred during the crystal’s fall to earth; it does not tell us where (or when) each change occurred. Indeed, each change could have occurred at any one of many stages in the crystal’s history. The larger a crystal is, or the closer we choose to inspect the crystal features, the greater the number of stages. Assuming that we can use a good-quality microscope to examine the crystal to 1/1000 of a millimeter, the number of distinct stages for our example is about 3800. At this point, we have everything needed to calculate the variety.

    Each of the 468 changes were one of two, equally likely types, and could have occurred in any one of the 3800 stages of the crystal’s growth. The resulting number of possibilities is a staggeringly large number: a one followed by 768 zeros or 10768. (For math-inclined readers, this is “3800 choose 468 times 2 to the 468th power.) To get an idea of the immense size of this number, consider that the number of atoms in the entire universe has been estimated to be a 1 followed by only 70 zeros or 1070. The number of snow crystals that have ever formed on Earth is much smaller - 1 followed by only about 35 zeros or 1035. If every crystal that grows under such cloud conditions has equal chance to be any one of these 10768 possible crystal forms, we can be sure that no two of them will be alike. Of course, Bentley instuitively knew this result. But it turns out that we cannot be so sure if we instead examined crystals that were born much closer to the bottom of the cloud. Crystals born near cloud base pass through fewer Bentley lengths, particularly so if the temperature is much warmer than –15 °C. In fact, one can argue that there probably have been two such crystals that appear the same.


Variety numbers

 For the crystal in the illustration, the number of Bentley lengths passed through is  468,  and, for the resolution we chose, the number of growth stages is 3800.

 The resulting number of possible crystal forms is about













 In comparison, the number of atoms in the known universe is about

          10,000, 000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000.

Whereas, the number of crystals that have ever formed on Earth is “only”


The Bentley length depends on fundamental properties of snow crystals and clouds. The values I used here were calculated from a few sets of cloud measurements and one set of snow-crystal growth measurements. As we learn more about both, the values will undoubtedly be refined. But they are still fundamental. The famous physicists Neils Bohr, Arthur Compton, and Max Planck have atomic length scales named after them, lengths learned by most students of atomic physics. Karl Schwarzschild has a size named after him, a size in black-hole physics that depends on the mass of the star, and Peter Debye has a material-dependent length named after him. Wilson A. Bentley now has one for snow. The Bentley length depends on temperature, but nevertheless represents a well-defined property of nature. Will meteorology and physics students in the future learn about the Bentley length? Whether they do or not, it is nice to know that Bentley’s name has been honored with a scientific term, an honor given only to a handful of scientists.

W. A. Bentley “Forty years’ study of snow crystals” Monthly Weather Review, Nov. 1924, page 532. He studied the crystals in the room, assuming they all started their growth under the same conditions. However, the editor pointed out in the article that the conditions throughout the room were not necessarily the same. Also, some of the crystals Bentley examined may have been born on the glass slide upon which he was photographing. The form of such crystals can be affected by the glass surface.

More details are in J. Nelson “Origin of diversity in falling snow” Atmos. Chem. Phys., 8 (2008), pages 5669-5682. Can be accessed at http://www.atmos-chem-phys.net/8/5669/2008/acp-8-5669-2008.html
A more careful calculation, in the above article, results in a slightly smaller number. But this difference does not affect the main points given here.

See the last page of C. Knight and N. Knight “Snow crystals”, Scientific American 228 (1973), pages 100-107.

See the final section of the article in reference 2.

News From The Gift Shop

The 2009 Snowflake Bentley Pewter Ornament has been designed  (see below) and modeled.  Casting will begin in March and will be ready for sale at the end of April.  Also in the Collection are our Scatter Pin, Necklace, Earrings and Zipper Pull using this beautiful Bentley snowflake design.


NEW THIS YEAR!  Vermont Snowflakes offering a Snowflake Bentley Charm Bracelet featuring five snowflake charms.  Details on the Bracelet will follow when the new Collection is introduced.

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Snow Crystals Vol. #14 February 6, 2008

Editors note

Bentley Birthday Bust by Wayne Howe
Jean Thompson in Jericho by
Duncan C. Blanchard
See the Snowflakes at Sax by Wayne Howe
Mr Bentley’s Electric Crystals by Jon Nelson
Bentley Makes New York Post
by Wayne Howe

Editors note by Peter Wolf

Well, another year has past and Bentley's Birthday is tomorrow, February 7th (Recent discovery that his birthdate is the 7th, not the 9th, as previously believed) with a welcome snow replacing the rain we had most of January.  One-hundred forty-three years ago Wilson Bentley was born on the Jericho farm where he lived his entire life. We continue our Jericho Center Weather conditions which are updated to a web page every 15 minutes and historical weather data charts are also viewable.  Bentley would record the weather conditions in a notebook throughout the day, each day, his whole life. Our current weather station records data automatically and I wonder if Bentley would rely on the new technology or the "old school" ways of manually recording the data?.

There is a Snowflake Celebration Feb 9th at The Community Center in Jericho Center celebrating Snowflake Bentley’s 143rd Birthday!! The celebration is at the Jericho Center Green - Saturday, February 9th, 2008, 9am-12pm.SCHEDULE OF EVENTS -9am Family Snowshoe Trek (BYO snowshoes), 9:30-11 Sled Dog Demo & Limited Rides for Children (Limited rides for 6-12 year olds with parental, 10-11 Crafts for Children, 10:00 Presentation by Elaine Salsbury -Snowflake Bentley’s Life, 10:30 Presentation by Stu Hall Photographing Snowflakes, 11:00 Community Snow Angel Flop, 11:30 Snowflake Bentley’s 143rd Birthday Celebration! Snowflake Bentley Look-a-Like Contest, Birthday Cupcakes, Fiddling, Sing-a-Long  Sponsored by and Raffle to benefit The Community Center in Jericho For more information contact: Orelyn Emerson 899-3853

Ray Miglionico from Vermont Snowflakes recently acquired a photo of Bentley that we have never seen before and we present it for the first time here.

We have an article by Duncan Blanchard  "Jean Thompson in Jericho", and a fascinating article from Jon Nelson "Mr Bentley’s Electric Crystals". We also received some new information from Wayne Howe on the discovery of Bentley's actual birthdate.

We still are getting a steady stream of requests for photos for publications ranging from news and magazine articles to textbooks and holiday cards from various companies. We are also looking for teaching materials on Bentley and snow, so please share your lesson plans/units with others through the message board or email us.

As always, purchases at the Gift Shop and The Old Red Mill help preserve the legacy of Wilson "Snowflake" Bentley. Thanks to everyone who supported us this past holiday season!!!

If you would like to contribute writings to this newsletter please

Bentley Birthday Bust by Wayne Howe

A careful reading of the town records have revealed that Wilson Bentley’s birthday is February 7th, rather than February 9th as recorded in books and biographies. Susan Merriam discovered the error when she read the original entriy with town clerk Jessica Alexander. “The date is clearly recorded as February 7th in beautiful script,” says Merriam, “someone else copied it incorrectly.” In Bentley’s time children were born at home and townspeople would come in to the Town Clerk’s the next time they were in the village. With so much written with the wrong information we expect February 9th  will still be the commonly accepted birthdate, but you now know the real story, Bentley was born on February 7th.

Jean Thompson in Jericho by Duncan C. Blanchard

Jean Thompson wanted to learn all she could about frost and snow crystals,  and there was no better teacher than Wilson Bentley. Jean, two years younger than Bentley, and a writer of children’s stories, first arrived in Jericho about 1904. She had married Henry Thompson in New York City in 1895, but the marriage ended in divorce in 1912. Jean and her husband had an income that let them enjoy life and to enter into the revelry of high society. She enjoyed beautiful clothes and the excitement of travel. They were friends of Charles Sanborn, the coffee man, and at times were guests on his yacht. Henry loved the good life and may have brought about the divorce by paying too much attention to other women at parties. They had no children and Jean never married again. In later years, Jean’s sister’s children joked that after the divorce she hated all males, even those only ten years old, for they had only one thing in mind.

Jean arrived in Jericho near the beginning of a successful career as a writer. She had not published many articles, but in later years would write at least five books, many poems, children’s plays, and nearly one hundred magazine articles. Her income went up and down like a roller coaster, but she enjoyed a steady reputation as a children’s writer who told exciting stories about animals and the beauty that nature paints on her huge canvas of the atmosphere. Jean’s numerous articles on snow and frost were so well-known that she was called The Jack Frost Lady. While doing research for these articles she must have heard of Wilson Bentley. A desire to know more about snow crystals and frost brought her to Jericho and Bentley.

For several summers she was a guest at Amy Nash’s boarding house on a side road that ran into the Nashville road barely half a mile west of Bentley’s house. It was a short walk between the two houses. Jean Thompson must have made the walk many times to visit Bentley and learn about frost, snow crystals, clouds, and nature’s other wonders of the atmosphere. The boarding house could not have been very large, for Amy Nash was also running a farm and taking care of her aging parents and her brother’s motherless children.

Though Bentley’s mother was living at the time of Jean Thompson’s arrival, the sight of this smartly-dressed city woman going to visit Bentley must have set tongues awagging among the neighbors, some of whom had never traveled more than a dozen miles from Jericho. Bentley, after all, had long been and was now one of the few eligible bachelors in the eastern part of Jericho.

Bentley lived in one side of a large farmhouse. His brother Charles and his wife and children lived on the other side. They too must have wondered about Wilson’s involvement with this woman. Was it really just to exchange ideas on the water wonders of the atmosphere? How many visits does it take to do that? Their children, sensing the questions in the minds of their parents, were well aware of the presence of Jean Thompson. Amy, one of Bentley’s nieces, remembering her said:

“Oh yes. Yes. He used to talk with her and she’d come overt here and see him a whole lot. . . . And I‘ll tell you a little joke. He was always playing jokes on people on April Fool’s Day. So one time they fixed up a joke on him. They told him she was coming and that she would be in Essex Junction. He got all dressed up and went to Essex Junction and she wasn’t there. But you know, he wasn’t even mad about that. . . . Yes, he was quite interested in her.”

Ruth Nash, a niece who was brought up by Amy Nash, and about age twenty  when Jean Thompson came to board with her aunt, had less charitable things to say about Jean:

“She was quite a [man chaser]. . . . Lots of people flirt for the fun of it. My aunt was disgusted with her. My brother and I just felt that Willie was nice to her and he was nice to everyone. . . . Unless I size Willie up wrongly, he never would have brought a woman like her into his mother’s home. Willie did not flirt. He was one of the serious minded people. . . . Mrs. Thompson spent several summers at Aunt Amy’s and one winter visit. She probably is   not of this world, but if she is, she will show up and try to horn in. So watch out. Her big interest used to be money, and I do not think she has changed any. . . . Aunt Amy heard plenty about Mrs. T., and she and grandmother did not like it. When she wrote the third year, there was no room for her. She tried to keep up the correspondence, but Aunt Amy did not answer. None of the Nash’s liked her. So I would just write her out of the picture.”

Willie Bentley may indeed have been “one of the serious minded people.” But he clearly did not share the Nash’s opinions of Jean Thompson. On February 20, 1907, in the first of only three surviving letters of the many they exchanged, Bentley wrote:

“Dear Mrs. Thompson,

Yours, telling of the operation you underwent, & of your continued  activities in a literary way, came duly to hand. I am glad to learn you are so well as to resume literary labors, altho [sic] doubtful of its wisdom just now, untill [sic] you give those eyes a good rest. I note with pleasure that Mrs. Stuart is to come for a stay with Amy Nash, & of course I shall go over and play for her if she cares to hear my amateurish melodies. Much has happened to me since writing you. On Feb 5 I secured the largest and most beautiful & valuable set of snow crystals that I ever secured from a single storm. Many odd rare ones, which I greatly prize.

On the 15th I went to Burlington & heard Prof. Moore, Chief of the Weather Bureau, lecture on Meteorology. You can imagine my pleasure when he threw some of my snow crystals on the screen, & spoke so highly of them. His references to me and my work were very flattering indeed. He seems to be a very bright forceful man, & I was very glad to meet him. I presented him with a souvenir of Vermont, & of his visit, an album containing many of the choicer snow & frost forms secured this winter. He was greatly pleased and interested in it.

Well, one lecture has come to me unsolicited, & I of course will deliver it, one on snow crystals, before the ”Social Club” of St. Albans, Vt. Kindly write me soon, that I may know how you are, & of your work.

                                                            With kind regards,
                                                            W. A. Bentley

            Jean Thompson replied to Bentley’s letter about a month later, and on April 8 Bentley wrote again. In this letter, even more than in the first one, it is abundantly clear that he held none of the Nash’s devastatingly negative opinions toward her. Several parts of Bentley’s long letter have been eliminated.

Dear Mrs. Thompson,

            Your letter, so full of good news, came to hand today, & gave me much pleasure, indeed. I am indeed enthusiastic over your prospects. They seem very bright, & I hope & trust no cloud will come to dim them. I am especially pleased at your prospects in regard to writing a new juvenile book. Hope you will succeed in securing contract for it, & will come & spend some of the beautiful summer days with us here in Nashville, while writing it. I am hammering away on the text of my own book, “Forms of Water,” and making some progress thereon. . . . I am much interested in your account regarding the book man and my autobiography. Hope I shall have the pleasure of returning the compliment sometime, & of giving some of those Encyclopedia fellows a sketch of yourself. But I have little hope, because they surely prefer to hunt you up yourself, & to hear from your own lips, & and through the medium of that charming voice of yours. I am also pleased & interested regarding those photographs for Magazine advertising purposes. It must be pleasing to you, & to whom would it not to sit for a photo to be used thus. I feel sure they will be good, & only wish one of them might be reproduced within the book “Water Wonders” so I might see it. . .  . I am exceedingly sorry to learn that your eyes are no better. . . . When writing, you should print but little. I am awaiting with great pleasure, the arrival of your book, which you have so kindly promised me.

                                                                        Very Truly yours,

                                                                        W. A. Bentley

This letter is remarkable not only in revealing Bentley’s warm feelings toward Jean Thompson and the imminent publication of her book, but we  learn for the first time about the writing of Bentley’s own book. He mentioned his book not only here and in his next letter to her but not in the rest of his surviving letters or in his published articles. What happened to this 1907 attempt at a book remains shrouded in mystery; it was never published and no manuscript has ever been found.

Jean Thompson and Wilson Bentley clearly had a mutual admiration society going, for she had talked to publishers or agents about having Bentley write his autobiography, and he looked forward to returning “the compliment “ by writing about her, but was certain that others would rather hear it  “through the medium of that charming voice of yours.” He hoped one of the pictures she sat for would appear in her book “so that I might see it.” This might have been a gentle hint to send her picture to him should it not appear in the book.

Just over two weeks later, on April 26, Bentley received her book in the mail. Her picture was not in it. He read it and, later that day, sat down and penned the last of his surviving letters to Jean Thompson. Though he could not possibly have been aware of it, some of what he said in that letter suggested a reason why his own book was never published. His letter has been edited for brevity.

Dear Mrs. Thompson,

            Your book “Water Wonders” which you so kindly sent me, came to hand today, & I had to sit down at once & read it through, & to feast my eyes upon the beautiful illustrations which it contains [Bentley’s own photographs!]. It is indeed a little beauty, & I am hoping that the number of copies sold will far exceed your utmost expectations, & bring you in handsome returns. You have added much and greatly improved the text, since I have seen the same, & this gave me an added pleasure while reading it.  It contains some errors, as I suppose all books do, but you have done finely in writing up subjects unfamiliar to you, ie, of which you have not made special studies in, & have presented them in a charming way, & are to appeal & reach the understanding of the young, & the average unscientific reader. What a beautiful book it makes, . . . I can imagine now what a thing of beauty my own book will be when issued, & it makes me almost impatient that it must wait so many months, before coming from the press. Yet it will be the better for it, of that I am sure. . . . As I write, the snow is falling, & there is already 2 inches on the ground. Permit me in closing, to heartily congratulate you on the successful publication of your book. I can imagine what intense pleasure must have been yours, when the first copy was in your hands.

                                                                        Very Truly yours,

                                                                        W. A. Bentley

Water Wonders, the “little beauty” so admired by Bentley, was Jean Thompson’s first book. Published by Doubleday as the eighth book in what presumably was a prestigious series on a variety of topics under the general title of “The Every Child Should Know Books,” Water Wonders was a 233-page account of the forms of water in the atmosphere and on the ground. She wrote extensively about dew, frost, snow crystals, and the formation of raindrops. Her eloquent and graceful prose was accompanied by no less than 154 photographs, all taken by Bentley. Not only were his photographs sprinkled liberally throughout her book, but so were his ideas, especially those on snow crystals and raindrops. Thompson’s book gave abundant testimony that the several summers she spent in Jericho learning from Bentley were not wasted. The master had taught his student well.

Bentley had seen an earlier draft of the book but not the final one. One senses his disappointment at not seeing the final draft when, immediately after saying he had read and enjoyed the book, he writes that “it contains some errors.” But he does not dwell on this bit of mild, implied criticism and softens it somewhat by saying he supposes that all books contain some errors, especially if the authors, like herself, are writing about subjects of which they are unfamiliar. Bentley is correct in saying she had presented her ideas in a “charming way.” She came to Jericho and Bentley an accomplished and competent writer who was his equal at crafting eloquent prose that painted vivid word pictures with metaphor and simile. She wrote that “the snow crystal is most ethereal, born in the vast spaces of the heavens, fashioned by the changing clouds and vapors, its lullaby the hoarse crooning of the “mighty blizzard.” To her, thunder is “Heaven’s artillery,” and the retreating clouds from a thunderstorm “leaden, ominous curtains . . . swept aside.”

Although published as a children’s book, it must have taken a highly precocious child to fully appreciate the ideas and beauty that covered its pages. Throughout the book Thompson used quotations from Shakespeare. Whittier, Lowell, and lesser known writers. Bentley observed correctly that it should appeal not only to young people but to the “average unscientific reader.” The book did well, and probably attracted readers of all ages. It was still in print ten years after its publication. Editors of Jean Thompson’s many magazine articles during that time were quick to remind readers that she was the author of Water Wonders.

The success of her book is quite possibly the reason why Bentley’s was never published. For what publisher would be willing to gamble on another  similar book, especially when Bentley had contributed most of his best photographs to Wonders and many of his ideas about  the forms of water in the atmosphere. His book probably was doomed the first day Jean Thompson showed up in Jericho.

After their summers of working together, can we conclude, as did Amy, her brothers and sisters, and possibly the Nash’s, that there may have been a romantic attachment between Bentley and Jean Thompson? Probably not. It seems unlikely. Clearly, they shared a passion in sensing the beauty of nature’s atmospheric wonders and wanting to share that with others, but that was it. Both in their early forties, they were far to set in ways that were worlds apart. He cared little for how he dressed, had no desire to travel far from Jericho, and lived only for the next winter’s treasures of the snow. But Jean Thompson liked to dress well, traveled extensively, and wanted to write about other things than the snow crystals.

No one seems to know how much they interacted after the publication of Water Wonders, though there had to be some, because many of her magazine articles were illustrated with his photographs. In his photographic notebook, in February of 1916, Bentley included her name along with others in a list of people to whom he wanted to send reprints of his latest articles.

Jean Thompson died many years after Bentley. Of the extensive correspondence that must have existed at the time of her death, little has survived. But among it were reprints of Bentley’s articles, several newspaper accounts of his death, and the three letters he sent her in 1907. 

                                                                        Duncan C. Blanchard

                                                                        January 2008

See the Snowflakes at Sax by Wayne Howe

The snowflakes that adorned Sax Fifth Avenue in New York City were stunning. The huge electric display of snowflakes, all based on Bentley’s photographs, creates a magical feeling on the street in the heart of mid-town Manhattan. A few pedestrians were so taken with the spectacle that they filmed it and put it on YouTube. You can view it at that site by entering Sax Fifth Avenue Snowflakes in the search window.

Mr Bentley’s Electric Crystals by Jon Nelson

Wilson A. Bentley was captivated by the beauty of snow crystals for most of his life. Perhaps then it should not be too surprising that he pondered the physical cause of their symmetry and intricacy. In doing so, he turned his mind to electricity. He considered that the crystalline surfaces had electric charges, with more charges concentrated at branch tips1. When the tips of the branches overflowed with charge, the charges dribbled down the sides to produce ‘growth nuclei’ for the sidebranches. This process, he argued, could explain the symmetry of snow crystals:

    "That the crystals, when permitted, attain to such a marvelous degree of symmetry and complicity, shows that the alignment of the growth nuclei, presumably tiny electric charges, is symmetrically regular to an almost unbelievable degree."

Here he connects electricity to the formation of sidebranches and the branch symmetry. In other writings, he connects snow electricity to growth rate, and snow electricity to lightning. In the specifics he was wrong, but in general he was surprisingly prescient. Snow crystals are indeed electric crystals, and the electricity itself is captivating. To see why, consider some of the amazing things that Mr Bentley’s electric crystals can do.

    It has been known, at least since Benjamin Franklin's experiments, that lightning in clouds is an electrical discharge. As for the charging, in 1860, William Thomson (later Lord Kelvin) suggested that the falling rain in the thundercloud was the charging current. However, Thomson did not specify how the drops got charged.  For a long time, nobody even suspected ice as a player. But in 1904, Mr Bentley asserted that, one, much of the rain in thunderstorms is, in fact, melted snow, and two, the snow is the source of the electricity. Other suggested mechanisms came and went. Yet it wasn’t for another 75 years before experiments and observations made it clear that indeed the electricity in ice is the main source of cloud electricity. Although the details of Bentley’s idea are inconsistent with current knowledge of crystal growth and thunderstorms, we should still give him credit for nominating electric crystals as the key player in thunderstorm electricity.  

     The current knowledge is this. When left by themselves, ice crystals apparently have negative charges on their surfaces and equal but opposite charges somewhere inside. As Bentley guessed, the amount of charge on the surface seems to increase when the crystals grow, with the greatest charging possibly being on the delicately branched crystals. When these crystals drift upward in a thundercloud, some of them ricochet off their larger, and blobbier, glazed-ice brethren, the hail particles. On average, they shed a little of this surface negative charge in the collision, leaving them with net positive charge and the hail with net negative charge. In each collision, about 10 to 100 thousand negative charges may be transferred. The large, negatively charged hail particles fall lower, and the small, positively charged ice crystals continue to drift upward until they can go no higher (about 6 miles above ground). Here, in the cloud’s upper reaches, a fist-sized volume of air may have tens of thousands of the crystals, so even if each crystal has only a little bit of excess charge, their cumulative charge can be huge. The ice collisions thus separate massive amounts of charge, putting negative charges near cloud bottom and positive charges near cloud top. This is analogous to rubbing a rubber balloon on your head: Each time a hair scrapes against rubber, the hair looses a little negative charge to the rubber. It may not be much, but the cumulative effect of many hairs and many rubs can transfer enough negative charge that, upon removing the balloon, you can hear the crackle of tiny sparks. In the thundercloud, it takes less than 30 minutes for these crystals to accumulate enough charge in the upper reaches for a spark to start. From the initial spark, one or more lightning bolts follow. Mr Bentley’s crystals can put on quite a show!

So, think about these little crystals for a moment – not only do they dazzle us with their beauty when they fall as snow, not only do they shape the land when they stack up in glaciers, but they also create the largest sparks in the world, sparks that have temperatures higher than anywhere else on Earth. Not bad for a tiny flake of frozen water. Not bad at all.

But that is not the only way the ice flakes show their electrical colors. The same charge exchange that happens with hail also happens whenever snow blows against something. In the windy plains, snow blowing against wire fences can deposit so much charge that the poor creature that gets too close to the fence may get knocked down by a spark2.  Elsewhere, tent-bound persons in a night-time blizzard have been known to see an electrical glow appear when they place their hand near the tent wall. In this case, each snow crystal that hits the tent charges the fabric a little bit more. The fact that a diffuse glow occurs instead of a spark is likely due to the tent fabric being a poor electrical conductor. This means that the current to the hand is slower and occurs over a broader path – a glow instead of a spark. A similar thing happens when an airplane flies through an icy cloud. The electrical discharge in this case is called St. Elmo’s fire, and it occurs on the outside of the plane.  And sometimes, we just hear snow’s electrical effects, as when snow blowing against antennas create radio static. These are just a few of the ways to experience Mr Bentley’s electrical crystal show.

The key process in all of this is the surface charges on the ice. So let’s look a little deeper into the matter and see where these charges come from. If we magnify a region of an ice crystal, such as the top view shown in (a) and (b) below, we see that the positions of the water molecules are nicely arranged in a regular order. This ordering has a honeycomb pattern. But if we look even closer, as in (c), the regularity gets a little messed up. The oxygens (black) in each water molecule sit nice and orderly in a hexagon, but the hydrogens (red) can be arranged many different ways. The only restriction is the Bernal-Fowler bond rule, which says that one hydrogen sits between every pair of adjacent oxygens. But it turns out that the hydrogens are notorious rule breakers, and it is a darn good thing too, as we will see later. 

      In many materials, the charges are carried by electrons. But the electrons in the H2O molecule are essentially stuck, unable to leave the molecule. Nevertheless, the hydrogens, which stick out like Mickey Mouse ears, have excess positive charge, whereas Mickey’s ‘chin’ has a corresponding excess of negative charge, as shown in (d). This +/– asymmetry makes H2O a polar molecule. Now, there are two ways that the polarity leads to a flow of electrical charge. Consider the charge flow as a dance; the oxygen and hydrogen are the partners, and the partners have two dance steps: the ‘hand-off’ and the ‘twist’. 

   In the hand-off, a hydrogen from one molecule is “handed-off” to the next molecule. If both molecules were originally electrically neutral, as in (e) below, the resulting hand-off (green-black arrow) creates a negative charge (OH-) and a positive charge (H3O+). Subsequently, a hand-off to OH- (or from H3O+) effectively moves the charge through the ice. When two crystals collide, OH- on the surface move from one crystal to another. The reason for the abundance of OH- on the surface is still a mystery, but the twist is probably crucial.

 In the twist, a water molecule rotates, effectively removing a hydrogen from one bond and transferring it to another. In the first twist in (f) below, the Bernal-Fowler bond rule gets broken twice: an ‘empty’ bond and a ‘double’ bond are created. In the second twist, the double-bond moves. The empty and double bonds are viewed as two types of charges, but personally, I have trouble viewing them this way. Instead, I think of the charges as arising from a coordinated dance move: When a chain of molecules do the twist, the end result is that the hydrogen positions have become a little more lined up. If we straighten out such a chain, as in (g) below, then the “+” in one Mickey-Mouse ear matches up with a “-” in a chin and the two cancel each other out. Only the “+”s on top and the “–”s on the bottom remain. In reality, the cancellations aren’t perfect, but the effect is the same: the “+”s on top pull on the OH-charges, whereas the “–“s on the bottom push (remember that opposites attract and likes repel). Here is the last important fact: the electrical dance has far more twists than hand-offs – about 10,000 times more. In other words, Bentley’s electric crystals prefer the twist to the hand-off. From what we can tell, all this twisting attracts the OH- to the surface. Once at the surface, these negative charges can move to another surface during a rebounding collision. And that is basically what we now know about the inner workings of the ice-crystal electric show. Enjoy.

  In a way, the electricity inside snow crystals is just as captivating as their beauty  outside. As we still do not know much about the electrical processes on the inside and the crystallization processes on the outside, the two may someday be found to be closely related, as Wilson Bentley first supposed. It is perhaps not too surprising that he thought about crystal electricity – at that time, electricity was portrayed as a kind of magical fluid. Magazine advertisements boldly asserted the wonders of electrical contraptions like J. Moses’s Electro-Galvanic Spectacles, Heidelberg’s Alternating Current Electric Belt, and the many strange-sounding electrical devices of Dr. Scott. They are all gone now, but we will always have Mr Bentley’s Electric Crystals. 


  1. This information and the quote are from Bentley’s unpublished notes, discovered and typed up by Duncan Blanchard.
  2. R. L. Ives, Weather Phenomena of the Colorado Rockies. J. Franklin Institute 226, 691 (1938).

Bentley Makes New York Post by Wayne Howe

The New York Post existed in Bentley’s time, so he might have gotten a kick out of a recent article in the paper’s Classroom Extra section. A third of a page is devoted to Bentley’s work, as part of a series meant for classroom use. Bentley, a staunch Republican, like almost all Vermonters of his time, might still recognize the masthead of the paper from his trips through the city during speaking tours later in his life. The article features a web link to snowflake Bentley and a science experiment kids can do.

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