524 F. II. Bigelow — Thermodynamics of the 



U,-U„ 



K 



v, — v„ 



is readily computed from the inner energy and the density, 



since v = — , and the volume increases with the elevation. 



P 

 Finally, the exponent of radiation 



K, /T,U 



can be computed from the K and T columns, and the result is 

 to show that the value of A is substantially 4 # 00, so that the 

 air radiates like a full black body, according to the Stefan 

 Law. It seems to be somewhat larger than 4 - 00 in the lower 

 levels and in the isothermal layer, and a little less than 4-00 in 

 the layers below the isothermal layer, as will be farther indi- 

 cated. A similar study of these thermodynamic data in the 

 diurnal convection near the surface, and in the cyclones and 

 the anticyclones, contains many points of interest that must be 

 discussed in other papers. 



The Mean Data for Europe, the North Atlantic Tropics, and 

 Victoria Nyanza. 



In Table 2 we collect the mean values of the data as com- 

 puted, five ascensions at Lindenburg, lat. +52°, one at Milan, 

 lat. 45°, five on the Atlantic Ocean from latitude +35° to —2°, 

 and two at Victoria Nyanza, lat. 0°. The variations in each 

 group, due to local conditions, are fairly well eliminated, but a 

 much larger series of computations would be desirable. The 

 temperature T seems to indicate an excess of degrees in the 

 high pressure belt from z — 2000 to z = 10,000, as shown in 

 my paper, Mt. Weather Bulletin, vol. 3, part 3, 1910. 



The isothermal layer sets in at 13,000 m. in Europe, 15,000 

 m. in the Tropics, and was not reported as reached at Victoria 

 ISTyanza. The gradients avei'age — 6'4 for Europe in summer, 

 — 6*0 in the Tropics, — 6"3 over East Africa. The gradient 

 ratio n is positive in all levels except where there is an inver- 

 sion of temperature, as shown in the isothermal levels. The 

 means here given in this layer were found by omitting from 

 the summation several of the results which are excessive, and 



T — T 



due to a small denominator in n =tft — tfr, where T : — T is 



often only 0-1° or 0'2° ; for T, = T , n= <x. The average 

 value of n is 2'0 in the levels 000 to 5000 m., 1*5 in the levels 



