Nineteen measurements of the vertical distribution of the wind velocity and the temperature are described. The distribution of the wind velocity was found to be well represented by a very simple formula of the logarithmic type: where u denotes the wind velocity, Z the height and a and Z0 are constants, a seems to depend only on the velocity at a given height and not on the stability and Z0 varies according to the stability, i.e.Z0 increases from a smaller value in the unstable atmosphere to a larger one in the stable atmosphere.
From the analogy between heat transfer and evaporation, the rate of evaporation from a finite pan by natural convection was obtained as follows: where E is the rate of evaporation in g•cm-2•see-1, C0, C∞ are vapour concentrations at the surface of water and in the air respectively, _??_θ0-θ∞, θ0, θ∞ being temperatures at the surface of water and in the air respectively, d is diffusivity, _??_; kinematic viscosity, β; expansion coefficient of air, g; acceleration of gravity and x is the radius of the pan in cm. Experiments were carried out by using a pan of radius 1.83cm. The range of _??_=θ0-θ∞ observed was from 0.1° to 50°C, in which θ∞ was about 20°C. The experimental result was expressed by while the theoretical formula for the pan at θ∞=20°C is Both results agree fairly well, but the experimental result gives about 21% smaller rate of evaporation than the theoretical formula.
Considering the effect of the negative adsorption of salt at the surface of a small drop of solution, the author calculated theoretically the relation between the radius of the drop and its saturated vapour pressure. The Gibb's adsorption formula is represented by (1), and by using this formula, the concentration of inner part of drop C is given by (6), where C0 and b are given by (4) and (7), and x, r and σ are the number of moles of salt in the drop, the radius of the drop and the surface tension of the solution with concentration C, respectively. Now, in the Thomson's formula (9), p represents the saturated vapour pressure over the flat surface of solution (concentration C), and then, the saturated vapour pressure over the drop of solution p can be calculated, given x and r. In the Fig. 2, the full lines represent the vapour pressure calculated by above mentioned process, for the drops which dissolves natriumchloride. The broken lines represent the vapour pressure calculated neglecting the effect of adsorption.
Greater and greatest sunspot activity periods were experienced for years 1770_??_1790, 1830_??_1845, and 1865_??_1880, during which famous Japanese famine known as Tenmei famine, Tenpo famine and Keiõ-Meiji famine occurred respectively. Such great famines were caused by very bad crops of rice in 2 or 3 consecutive years in the above periods. The 4th great spot activity is now going on. The mean annual sunspot relative number for 1948 was about 153 and the mean for 9 months in 1949 was about 154, while that in 1778, 1837, and 1870 were respectively 154.4, 138.3 and 139.1. From analogy of those past experiences, we are compelled to be anxious about similar worst rice crops which will be taken place in some future years during coming 15 years in which next spot minimum and maximum periods will occur.