404 



SHORT MEMOIRS ON METEOROLOGICAL SUBJECTS. 



where 

 and 



a = 7.4475 



h = 234.69. 

 If we take the logarithms and differentiate, we obtain 



ah 

 = j]i . — 



e 



de 1 Tj- 

 dt 



and after introducing the numerical values 



de 



at 



[3.00472] 

 (:i34.7 + tf ' 



where the number inclosed in brackets is the logarithm of the product 

 of Ma h (^), the latent heat r of aqueous vajior at diiferent temperatures 

 is computed according to the formula of Clausius, 



r = G07 — 0.780 t. 



P'or the temperatures below 0° is still to be added the heat liberated on 

 the passage of water from the fluid to uhe solid condition : it amounts to 

 80 calories. Since, however, at 0°, vapor can be condensed in a fluid 

 form, I have computed the diminution of heat without including this 

 additive heat for 0°. The differences are, however, quite unimportant, 

 since, for 760 millimeters, we have dli = 0.63 for i = — 0°, but = 0.05 



for f = + Oo ; for 200 millimeters, we have ^ = 0.38 for f = - 0©, and = 

 0.40 fort =4-00. 

 The table thus computed is as follows 



d/t 



Diminution of Temperature for each Hundred Meters of Ascending Saturated Air, in Centi- 

 grade Degrees. 



Value of q in grammes or the iceight of the aqueous vapor in a kilogram of saturated ayr. 



Value of ~. — in units of the fifth decimal. 



e dt 



7971 7628 7306 7005 6721 6455 6204 5967 5744 



