EQUATIONS OF FOG CHAMBER. 



6l 



Similarly 



p 2 - 7r =(p 1 - 7n) c / fe ( - 7i)( k -)/ k , 



v/r^((p - n)l{p x - 7r 1 ))(M/* ) r/r/ = ((/>' - x)/(p t ' - n x f ))^-c)/k 



Making use of the values of table 18, the data of table 216 were com- 

 puted on a single approximation. 



Table 2 i&. Corresponding to table 18, when both fog chamber and vacuum chamber 

 are saturated. v/V =0.064; temperature 20 ; ir 1.7; =76 cm. 



Assumed from data for t Jt f\, in table 18. 



(P-P2)/(P-P 3 )- 



= OJO 



I6.4 



23-5 



^= .6 9 

 14.2 



The corrections (see table 216, and upper graphs in fig. 30) again 

 lie on a curve which passes through zero, but with a larger slope. In 

 fact, they are so much larger than the preceding cases and throw the 

 whole phenomenon into so low a region of pressures that it has seemed 

 best to abide by the data at the beginning of this paragraph, at least 

 for the present. Details are given in table 21b. 



A few incidental results deserve brief attention. The first of these 

 is the nearly constant difference of about op 2 = 2 cm. between the ob- 

 served value of p 2 (nominal) and p s . Since for dry air or not 



{p' 2 -7t)+v/ V. (p 2 -x) = (p 3 - it) (1 +v/ V) 



is constant for a given exhaustion, 



dp' 2 = -v/V. dp 2 . 

 Hence if dp 2 = 2 cm. 



^'2 = 0.064X2 = 0.13 cm. 



