A CONTINUOUS RECORD OF ATMOSPHERIC NUCLEATION. 



131 



The question is most conveniently stated for the middle plane, x = a/2, 

 inasmuch as the saturation here is least. Since at 20°, fe = .23 cm'/sec, about, 

 the results, if ^^ = o initially, are shown in table i . If the initial saturation is 

 p^ = 1/3 or 2/3, the data, as the table shows, imply successively greater satura- 

 tion throughout than in the preceding case. As the relative saturation left 

 after any exhaustion would not probably be less than 2/3 even in the absence 

 of convection, the inferior limit of saturation shown by these data is excessive. 



:/ £3456789 



Figures 2, 3, 4. — Graphs Showing the Progress of Diffusion in the Lapse of Time. 



The upper graphs, figure 2, contain the relative saturation pressures as 

 ordinates at the tinies given by the abscissas in minutes, according as the initial 

 pressure is p^ = 0,^0= 1/3. oi" i'o = 2/3. 



TABLE I.— DIFFUSION OF WATER VAPOR BETWEEN OPPOSED SURFACES; 



a = II cm., X = 5.5 cm., k = .23. 



Thus in 3 or 4 minutes the air plate in the trough may be considered satu- 

 rated under the most unfavorable conditions. In the aspiration of fresh air 

 through the trotigh the maximum rate was about 4.5 lit./min., the usual rate 



