On the Habit of Ice-Crystals Grown in the Atmospheres of Hydrogen and Carbon Dioxide

Abstract

In order to study the factors which determine the habit of the ice-crystal, a series of experiments on the mode of growth of ice-crystals grown in gases into which water vapor diffuses at different rates have been conducted. In the present paper, results of experiments with air, hydrogen and carbon dioxide are given.
In air the mode of growth of ice-crystals at water saturation changes markedly with temperature; at -7°C growth rate along the principal axis is much larger than that along the lateral axis, but at -16°C the former is smaller than the latter. The results of examination of ice-crystals grown at -7°C and -16°C in the gases mentioned above show that the difference in the growth habit with temperature as mentioned above is pronounced in the case of carbon dioxide as in the air, but much less pronounced in the case of hydrogen atmosphere. In hydrogen gas the growth velocities in both directions are nearly equal. This tendency was found in the mode of ice-crystals formed by two different methods; one formed by AgI seeding and the other formed on rabbit hair in a cold chamber. In the latter case, air and hydrogen were filled in the chamber by turns during the growth of an ice-crystal and the corresponding changes in the modes of growth were observed.