Let it snow! Cool books from the CHF collections

Everyone knows that no two snowflakes are alike. Some of us have to shovel snow in the winter, and a few of us have kept some childlike wonder and try to catch snowflakes on our tongues when no one else is around. But throughout history the keenest insight into the tiny masterpiece of nature that is the snowflake has been granted to those men and women interested in snow from a chemical perspective. The books in the Othmer Library at the Chemical Heritage Foundation tell the story of snow and men across millennia and spanning the globe. 

Chinese snow: hexagons and sorbet
The people of ancient China had eyes and a mind for observation, and so it is not surprising that they noticed something curious: raindrops and hail look like little balls of water, but snowflakes invariably take on the shape of flat, six-pointed stars. One of the greatest achievements of the Chinese, however, lies in their practical use of snow: they mixed it with fruit, wine and honey, and thus created an early version of sorbet with a twist. They also figured out that their ice cream would be less watery if they packed a mixture of snow and saltpeter directly outside containers filled with syrup. And who would have thought that sorbet and warfare have something in common? Indeed, saltpeter is a main ingredient another famous Chinese invention—gunpowder.

Sweet nothings: Kepler and Descartes
The essay which is now considered the first “scientific” investigation of the hexagonal form of snow crystals was written by the archetypal poor scholar. When he could not afford a Christmas present for a friend, German astronomer Johannes Kepler, who resided in Prague at the time, produced a little essay on the snowflake—a perfect present, “since [a snowflake] comes down from heaven and looks like a star.” Among other things, Kepler tried to find an explanation for the unique shape of snow crystals in geometry and mathematics.

He was not the only one dazzled by snow. A few years later, while traveling all over the Netherlands , French philosopher René Descartes sat down to describe the shapes of snowflakes in a systematical manner, including the rare forms of twelve-sided snowflakes. But neither of these great men cracked the code of the nature of the snowflake.

Getting hooked on microscopes: Hooke and Mairan
In late–seventeenth–century London, the famous polymath Robert Hooke observed snowflakes through the latest state-of-the-art instrument: the microscope. The difficulties of catching a snowflake, placing it under the microscope on a very cold slide at an appropriate angle and fast enough to see it before it starts melting, also occupied Hooke’s contemporary, French physicist Jean-Jacques d’Ortous de Mairan, who was working in Paris. Mairan also found it impossible to compare the snowflake under (or on) his own nose with those described or drawn by other scientists. For a long time, research on the snowflake was almost like catching sunlight in a bucket.

Picture perfect: snowflake photography
"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."

These words were spoken not by an artist, but by Wilson A. Bentley, an American farmer in Vermont who, in the 1920s, found a way to photograph snowflakes and solved Mairan’s problem of how to catch a snowflake. His technique involved a blizzard, an open window, a black wooden tray, and a very light hand to place a single flake from the tray under a microscope. Capturing ephemeral beauty must have made him very happy: altogether, Bentley took more than 5,000 photos of snow crystals. Two thousand of them were frozen in time when his book of photographs was published shortly after his death.

Answers to snowflake questions
The next unlikely candidate for snow studies was also the scientifically most influential. Japanese nuclear physicist Ukichiro Nakaya landed a job at a university without nuclear research, but situated in an area with lots of snow: Hokkaido, the northernmost of Japan's four main islands. He drew up a definitive system of all snow crystals, including irregular ones, and was the first man to grow artificial snow crystals—an amazing achievement considering that even nature produces them erratically.

As for the shape of snowflakes, we had to wait for X-ray crystallography to be developed to explain it. It has been less than a century since scientists found that the answer lies in the arrangement of atoms in a snow crystal. By the way, there is no scientific reason why two snowflakes should not be alike. Watch out next time you catch snowflakes—you might be amazed.

View the books and other related items in the Othmer Library catalog

• Robert Hooke’s Micrographia (1665)
• Frozen urine and refrigeration anesthesia may be looked up in Thomas Bartholin, De nivis usu medico observationes variae (1661)
• Images from Jean-Jacques d'Ortous de Mairan’s Dissertation sur la glace (1749)
• W. A. Bentley’s Snow Crystals (1931
• Ukichiro Nakaya’s work, both in English (Snow Crystals, Natural and Artificial (1954))
• ...and in Japanese (Shimo no hana [Frost flowers], 1950)
• John Tyndall, The Forms of Water in Clouds & Rivers, Ice & Glaciers (New York, 1872)
• J. H. Frandsen and W. S. Arbuckle, Ice Cream and Related Products (Westport, Conn., 1961)
• W. S. Arbuckle, Ice Cream (Westport, Conn., 1966)
• For early images of salt crystals, see Henry Baker, Employment for the Microscope (London , 1753)