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Growth rates of basal and prism faces of ice crystals from the vapour phase have been measured as functions of the supersaturation at infinity from the crystal surface at -30* and at air pressures 250 and 0.3 Torr*.Contributions of the volume diffusion process of water molecules, the surface kinetic process and the conduction process of the sublimation heat to the measured growth rates have been quantitatively discussed on the basis of theoretical consideration in the companion paper (Kuroda, 1984). The dependence on supersaturation at the crystal surface and air pressure of the kinetic coefficient or the condensation coefficient has been obtained by combining the theory of the companion paper with the experiments.It should be noted that an increase in air pressure makes not only the diffusion process slower, but also the surface kinetic process inactive.

Life times of water drops before breaking suspended freely in a vertical air stream have been empirically determined as a function of drop diameter. It has been found that breaking probability of a drop increases with increasing drop diameter. Average life times are 273 sec at 5.5 mm, 63.4 sec at 6.5 mm and 10.1 sec at 7.5 mm. An empirical formula obtained (average life z sec at D cm in diameter) is =3.40x106e-17.0D. The number of droplets produced by breaking of a drop increases with diameter of the drop. Empirical formula is obtained for the size distribution of the droplets. No marked difference is found between the results of the experiment at a room temperature and those at 0°C.

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