5 



VAPOR NUCLEI AND IONS. 



It may be of further interest to compute the values of p-p 3 for v/V = i 

 (a small exhaustion chamber) and for v/V = o (one of immense size) 

 for the same values of p, p', p 3 , observed isothermally and initially at 

 the fog chambers and vacuum chambers and finally when both are in 

 communication. The results for 20 are given in table 19, page 56. 



These data are charted in figs. 28 and 30, to a first approximation, in 

 terms of v/V and p 3 . If expressed in terms of p', they lie nearly on 

 straight lines, as do the above values of p 2 for v/V = 0.064. The large 



45 50 55 60 cm. 



Fig. 27c. Wet air in both chambers. Table 20. 



variation between v/V = and 0.064 as compared with the small one 

 for v/V = 0.064 and 1.0 is noteworthy. Hence, in using small vacuum 

 chambers, the observed and computed p 3 and p 2 lie more closely together, 

 but other disadvantages supervene. The rate of variation 



dp, 



= P*{p/p') {k - c) / k 



(p/p f ) {k-c)/k 



d{v/v) *""* {1 - (p/p')^-t)/ k .v/vy 



is always negative and proportional to p 3 and (p /p')(. k - c )/ k . 



