526 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 51 



m 



h = 6000 m g = 9 . 8 2 for the average altitude 



sec 

 R 0.41 



R = 287 



C p 1.41 sec 2 Cent. 



;;r Calories 



C * = 9S7 s^C ent To = 0.2375 - kgC y 



P l = 770 ram mercury P, = 740 ram mercury 



r, = 285° C\ 7, = 288° C. 



dT\ g C° (dT\ 



— = - -=-= - 0.009929 , ) = - 0.006 



dz / t C v m \ dz / 2 



r, = 225.4° t 2 = 252°.2 



We assume the vertical temperature gradient in the column 

 P 2 p 2 to be constant : it is very nearly equal to its average value for 

 moist air saturated at the temperature 15° C. at the sea level. 

 Using the hypsometric equation for linear vertical temperature 

 gradient 



dT 

 p IX \~g/R'dz 



P = \T/ 



we compute 



p, = 343.62 mm P 2 = 345.92 mm mercury 



and using the analogous equation for adiabatic temperature 

 gradient 



R/C v 



xJ = 251°. 51 C. 



The quantity of heat to be communicated to a kilogram of air along 

 the vertical path P 2 p 2 is 23.6 C p = 5.6 calories. Air saturated at 

 15° C. and 74o mm contains 0.01086 kg vapor for each kilogram of 

 dry air; assuming the latent heat of evaporation to be 595 there- 



