Preliminary Experiments on the artificial Production of Snow Crystals

Abstract

In the preceding paper, Investigations on Snow No. 6 1 ), the authors described the results of experiments on the artific'ial production of frost crystals with reference to the mechanism of the formation of snow crystals.In those experiments .theauthors attempted to infer the mechanism of producing various types of snow crystals from knowledge gained from the artificial formation of the correspOl~ding frost crystals.In the spring of 1935 the authorities of the Hokkaido Imperial University begal'i to build a cold chamber laboratory and it was completed at the beginning of 1936.This laboratory is provided with a cold chamber 4 X 4 X 4 ,metres in dim ension, the whole chamber being designed to be cooled down to -500 by a refrigerating mechanism.The former experiments on the artificial frost crystals were carried on in this cold chamber and further the authors succeeded in producing a, snow crystal which has six dendritic branches extending outwards almost symmetrically' from a nuclear centre.The nucleus of this artificial snow crystal was suspended by being attached to a thin rabbit hair or cotton filament.Various types of.snow crystals were produced by varying the temperature of the air where the crntal is made and that o~ the ascending water vapour.The results are described in this paper, although they, are still of a preliminary nature. The Apparatus~Two sets of apparatus were used for thisexperi,ment., Apparatus No.1 is almost the same asthat used in th~ experiments described ,in report No.6 and is shown in Fig. L B is ,a cooling vessel p1aqy of copper sheet~ and Investigations on Snow, No. 10. 1) U. NAKAYAand 1.