The characteristic properties of rain-falls brought by typhoon and by other disturbances were examined of observed data at Tokyo and Naha for past. 10 years. Intermittent down pour is found to be the most remarkable character of typhoon rains But for this conclusion more study is required.
In summer of 1944 Observations of fog were done at Urakawa in Hokkaido. Results obtained are as follows: (1) Trabert's fcrmul_??_. on the relation between the visibility and fog particles holds only when the altitude of the sun, the height of fog etc. are the same and in different states the constant value in the formula has different value. (2) Fog particles become small as they invade into the inland and this can be explained as due to the high temperature of the air on the ground. (3) Often, fogs hecome thin during the rain fall owing to the capture of rain drops and this was ascertained quantitatively by experiment. (4) The rate of evaporation of a fog particle at rest is proportional to the square of its diameter.
An apparatus which is capable to measure a small pressure and its changess in the circumstances of low temperature and pressure was devised, The main part consists of a capsule which has a thin plate of mica (for the lack of hysteresis and the small temperature coefficient of elasticity) and is contained in a glass case in order to isolate the capsule from the surrounding. The mica plate consists of one plate of electric condenser, the other is a fixed metallic plate over the mica plate. A pressure difference to be measured is introduced between mica capsule and glass case. The deflection of mica due to pressure is transferred to the change of electric capacity, and then measured by the electric apparatus with sensitive devices of vacuum tubes (oscillator, detector and amplifier.) The main difficulties of measurment consists in the construction of mica capsule and the stable adjustment of electric parts. The maximuz sensitivity obtained is 12.5 volt/cm.
The transmissivity of heat radiation through the various kind of smoka, viz. zinc chroride, heavy oil and coaltar, was examined by the field observation (see fig.), and we have ascertained that about 70-80% of heat radiation passes through such dense smoke that the terrestrial objects behind it can not be seen at all by the naked eye. The detail of the experimental arrangement and the method of observation together with the results of observations will be reported in Geophysical Magazine in English in the near future.
When we calculate the wind velocity from the pressure difference in wind tunnel, it is very complex to calculate by slide rule or calculator; then, on the occasion when we give official approval to Robinson's cup anemometer by wind tunnel, the calculation is very hardfull for the routine use. So I try to calculate the velocity easily by nomograph. The nomograph is a collinear one that has four variables and these variables are wind velocity, height of alcohol in manometer, specific gravity of alcohol and air density.