  There are few photographers who appear to be aware of the many beautiful phenomena of nature that can be studied by the aid of photography. Under the title of "Schnee Crystalle," Dr. G. Hellmann has published FIG. 62.—SNOW CRYSTALS. PHOTO BY DR. NEUHAUS. Dr. Neuhaus describes his method of photographing snowflakes in Dr. Eder's Jarbuch, from which article we extract the most important and interesting paragraphs: Were we to attempt to photograph snow crystals in a perfectly cold room, the temperature is still higher than that out of doors; moisture at once precipitates upon the carrier of the object; the crystals would melt and evaporate after a short time. The work must be done in the open, and perfect success can be expected only when the temperature is near zero. FIG. 63.—SNOW CRYSTALS. PHOTO BY DR. NEUHAUS. Snow crystals evaporate rapidly even in low temperature, and the work requires to be done rapidly and with caution. Freshly fallen snow only will give a good photograph, and as we are compelled to work in the midst of the snow storm, the task becomes still more complicated and difficult. Snow crystals but a short time after falling break, the broken pieces freeze together and crystallization is destroyed. For the illumination of snow crystals, transmitted light only can be used; reflected light destroys the shadows, and injures the high Photo by Martin. Diffused light, especially that of a dark winter's day, and during a snow storm, is not fit for this kind of photo-micrographic work, and we must resort to artificial light, preferably to that of a petroleum lamp. To prevent heat action emanating from the illuminating ray cone, an absorptive cell of alum FIG. 65.—PHOTOGRAPH OF FROST CRYSTALS. Dr. Neuhaus has made photographs of more than 60 different ice and snow specimens. The pictures of ice crystals much resemble those of hoar frost, deposited after a cold winter's night. Of snow crystals, the doublets are highly interesting, two crystals merged into one, and those having passed through FIG. 66.—PHOTOGRAPH OF FROST. The most difficult question of all remains, the cause of the various forms of the hexagonal crystals, which frequently change in the same snowfall. Instead of advancing a new hypothesis, says Hellmann, it is better to acknowledge that we know nothing positively in regard to this. In our knowledge of the form and structure of the snow we have made great advance since the time of Kepler, but after nearly We do not know the special conditions which determine the formation of one or the other form of snow crystals. We have found that a low temperature favors the formation of tabular crystals; a higher temperature the star shaped crystals; these groups show such multifarious forms that it is necessary to seek for other causes which influence the formation of snow figures. There is offered here a broad field for new investigation and study. We give a reproduction (Fig. 64) of a photograph of a curious group of crystals. Some water had been left in a 10×8 dish on a winter day, and a film of ice was seen floating on the surface. The formation of the crystals and the floral design were so beautiful that it was taken out and photographed. The delicate lace-like edging of the glacial tracery is the result of the deposition of hoar frost while draining off the water from the ice leaves and flowers and fixing the image in the camera. Quite recently Mr. Jas. Leadbeater has favored us with some account of his beautiful work in this fascinating branch of photography, some samples of which are here given. He first makes his windows perfectly clear and waits for a keen frost. The camera is inside the room and a dark cloth-covered board is placed on the outside, leaning against a low balcony of wood. The exposure varies with the thickness of the crystals, from two to ten seconds, principally with a very small stop. Two reproductions of his pictures will be found on pp. 76-77. |
|
