12 CONDENSATION OF VAPOR AS INDUCED BY NUCLEI AND IONS. 



of water precipitated per cubic centimeter of the exhausted fog cham- 

 ber is 



c - 



= 



fl-Tl) 



If the coefficient of d in the above equations be written x, 



pcx P cx _ 



L, L TI 



where a and b are constant, so that T is the temperature at which the 

 line d, T, crosses the vapor-pressure curve d=f (rj, which for water 

 vapor is known as far as 50 C. In place of absolute temperatures r, 

 degrees centigrade / x and t t may be used. Table 5 contains a series of 

 useful data for m, dp (if = 76), dp/p, vjv, t lt and t r 



TABLE 5. Water precipitated at different exhaustions and temperatures. 



^ = 76 cm.; dp 3 =p-p 3 cm. 



To compute p 2 and p' 2 the equations are 



and p'a-TT-- 

 P i 



i-c/fc 



where p l / p v depending upon Boyle's law, will have the same value as 

 before (section 7) and in the approximate form becomes 



Since 



Pi * 

 pi 7i 



Pi 



with a similar equation for p' lf the pressures p^ and p\ may be computed, 

 since the values of the second member of the equation are now known. 



