DISCUSSION 263 
Dr. Choji Magono—As the crystal type is very 
important in the formation of snowflakes; what 
type did you use in the experiment? 
Dr. Hosler—We had plates, columns, and 
needles but because of the temperature range 
along our wind tunnel it was difficult to control 
this. However, we can work with plates or nee- 
dles by just changing the environment we are 
creating. 
Dr. Magono—Did you use dendritic types? 
Dr. Hosler—No, we were unable to obtain 
them in our small chambers. Perhaps the Swiss 
can get dendrites. In ours, we must wait a long 
time before we get dendrites. 
Dr. Magono—In nature we find that snow- 
flake formation begins at an air temperature 
warmer than —10°C. 
Dr. Weickmann—(communicated) Dobrowol- 
ski in his fundamental but little-known work on 
snow-crystal observations in the Antarctic (A. 
Dobrowolski, La neige et le givre—Rapports 
Scientifiques; Résultats du voyage du 8.Y. Bel- 
gica en 1897-1898-1899; La Météorologic, 1904) 
gives the following table on the dependence of 
snowflake occurrence from the ambient tempera- 
ture: 
Snowflake 
Temperature occurrence 
+1.0 to —5.0°C 83% 
—5.1 to —10.0°C 9% 
>—10°C 8% 
