In the previous paper, we described the method of measuring the friction of snow and obtainning the accurate value of its friction without any influence of front drag and scale effect due to size limitation by our rotational friction tester though this effect could not be escaped even in model ski or sledge method, and proved that the degree of accuracy of μ_S and μ_K fell within the limit of ±0.05. Also we proved that μ_S and μ_K took constant value within cedtain pressure range (2166g/cm²) and that μ_K took constant value within certain sliding speed range (0.0057.2m/sec.)
In this paper, we have described the result of the measurement of friction of plastics on snow and we proved that μ_S was affected by air tempeeature, snow temperature, watercontent of snow, the kind of plastics, its water absorption and roughness of its surface, and that μ_K was affected by air temperature, snow temperature, water-content of snow, sliding speed, the kind of plastics and water absorption. But it was not affected by the roughness of its surface. Accordingly there are some factors which are not common in them.
Furthermore, we proved that, when the watercontent of snow increased, μ_K increased abnormally and μ_S decreased on the flat sliding surface, and consequently μ_K>μ_S.
As this abnormal phenomenon would be due to interaction of water and smooth sliding surface, we have overcome this with rough sliding surface.
As for the relation between the nature of plastics and μ_K on snow, we proved that μ_S showed fairly large value when the contact angle of plastics with water was larger, μ_K on snow showed different value when the method of synthesis gave difference of hydrophillic properties. As for mechanism of this phenomenon, we will report in near future.

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The catching characteristics of conventional snow gages are quite unsatisfactory.
Yoshida and Saito observed the catching rate C of various snow gages and found that C was given by the following empirical formula,
C=1/(1+mv)
where v is the wind velocity in m/s near the gages orifice and m is the constant for certain snow gage. For J.M. A. standard 20-cm standpipe snowgage m was 0.449.
In order to secure high catching rate, it is neccesary to undisturb the air current above the orifice.
The authers designed a snowgage which had the funnel-shaped head connected to an U-tube. The funnel and it's side of the U-tube is filled with kerosene and the other side is filled with water. The whole system is heated to a certain temperature above 0°C. When the snowflakes enter in the oil, they melt and fall down as waterdrops into this U-tube, and the same mass of water of these drops must overflow from the opening of the water side of the U-tube. The overflown water is measured by the jar for raingage.
From the analysis of the results of field tests, the catching rate of this snowgage is presumed to be shown by the following formula.
C=1/(1+0.24v)

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To protect from the damages caused by the avalanche, the Japan National Railway forests the defence forest and builds the defence pile on the slope where an avalanche is threatened.
To find out the bending strength of the defence forest tree and the defence pile agains the pressure of the snow cover on the slope, the trees were classified according to the size of diameter while the defence pile was classified according to the material, and then each of them was pulled by a wire rope in parallel with the slope and the maximum bending strength just before its break was observed.

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