So far the solid nucleus which is insoluble in water has been treated in the same way as the water drop of the same size in condensation processes, and it has been considered that such nucleus cannot act as condensation nucleus in the atmosphere, because the maximum water vapour pressure on it is higher than that on the hygroscopic nucleus. However, when such nucleus is wetted fairly well by water the adhesive force of water to the solid nucleus is larger than the cohesive force of water, hence the maximum water vapour pressure on the solid nucleus is lower than that on the water drop of the same size. Therefore, it is clear that such nucleus can act as condensation nucleus more effectively than the water drop of the same size. The author investigated thermodynamically the stability of the thin water film formed on such a solid nucleus and obtained a formula which expresses the saturated water vapour pressure on the film, namely where k: Boltzmann's constant, P_??_, h, maximum water vapour pressure in equilibrium with the water film with thickness h formed on the spherical solid nucleus with radius R, P∞: maximum water vapour pressure on the plane water at the absolute temperature T, σ: surface tension of water, υB: molecular volume of water, ε: ratio between the adhesive force of water to the solid nucleus and the cohesive force of water, U∞: evaporation energy of water of large mass referred to one molecule, δ11: distance between two neighbouring water molecules. From the above result it was found that the solid nucleus which is wetted well by water and is larger than 10-5cm can act as condensation nucleus in the atmosphere.
The small particles of the sea water which were made by means of specially constructed spray equipment at the rate of 10c.c. per second were introduced into an air tunnel having an air current velocity of 1.3m per second and a length of about 3 metres. Then, in the air tunnel, these small particles were caught at three positions along the horizontal line of 50cm in length under the central line of the tunnel, on thin oil films laid on plate glasses. The dimension of the fallen particles caught on the thin oil film on the glass were measured by ocular-micrometer and mechanical stage equipped on the low power micrometer. Let it be d cm. On the other hand, let d0 cm be the dimension of the particles which were separated from the nozzle of the spray equipment on supposition that the particles were fallen on the above mentioned positions at the resultant velocity which was composed of the terminal velocity and the air current velocity in the tunnel. From the above two values d and d0 the percentage of evaporation of the particle e=(_??_/d0)×100% was obtained. On the result, the apparent percentage of evaporation at the distance of D=92cm, D=159cm, and D=206cm from the nozzle of the spray equipment were 77.5%, 82.6%, and 90.3%, respectively.
We observed the annular eclipse of May 9th, 1948 at Rebun Island, Hokkaido. By equipping the direct solarimeter with a photo-tube at its base and with a filter having a maximum intensity at 5000Å at the entrance of the cylinder of this instrument, we observed the solar radiation by a pointing galvanometer and obtained a satisfactory and splendid eclipse curve. Before the commencement of the eclipse we obtained the coefficient of transmission p=0.8 by observation. By the eclipse curve we studied the effect of the limb darkening. The results were as follows: From radius r=0 to 0.95 on the sun's disk (the radius of the sun's disk being taken as 1) the radiative equilibrium is predominant, i.e., I(r)=I0(1-U+U√1-r2) and U=1/5, where I0 is the intensity at the sun's certre. While from r=0.95 to r=1.0 the convective equilibrium is prevalent, i.eI(r)=I0(1-r2)2(C-1)/CC=5/3.
The aim of this paper is to investigate the mechanical properties of the astatic-magnet variometer, which is being used recently for the particular observation of minute variation of geomagnetic field. The characteristic feature of this apparatus is noted comparing with the single-magnet variometer. The sensitivity of the astatic-magnet variometer is defined both in the statical and dynamical cases, and the most convenient method for measuring sensitivity is discussed. Finally, the experimental results made at Kakioka Magnetic Observatory are shown in connection with the above discussion.
The well known fact, that the coefficient of turbulent diffusion of the atmosphere is proportional to the 4/3 power of the scale of phenomena, was explained successfully by Weizsäcker by means of the modern turbulence theory. The author expected that this law is also applicable to the oceanic turbulent field, and ascertained it by the accumulation of many observed results. As an emp_??_ical formla, the relation K=0.01L4/3cm2•sec-1 was obtained. The difference between the coefficient of turbulent heat diffusion and that of turbulent momentum diffusion was explained by the concept of turbulent Prandtl number. And as the similarity law of the model tests concerning the oceanic phenomena, the concept of turbulent Reynolds number was introduced.