NUCLEATION CONSTANTS OF CORONAS. 



appear, reasons for which are outstanding. As a rule smaller values of 

 n are observed than should occur, particularly for the larger coronas. 

 As a means of standardizing the fog chamber, therefore, this method is 

 again inapplicable ; moreover, strictures are cast on the present theory 

 by Chapter VI, where dn/dt = a bn 2 is called in question. 



55. Distributions of vapor nuclei and of ions. In tables 38 and 

 39 I have collected data for the number of nuclei and of ions found in 

 apparatus II, under different conditions. Not only is a new fog chamber 

 used here, but the method employed is the one described in the present 

 chapter. Contact is therefore made between the fiducial annuli of two 

 coronas, and the distance apart of the sources of light or the double 

 tangent S, on a radius of 250 cm., at which contact occurs, is measured. 

 Special work was also done to determine the fog limits; and in case of 

 the vapor nuclei of dust-free air, the initial region of ions is explored in 

 detail (table 39). The table contains the adiabatic expansion v 1 /v and 

 the relative adiabatic drop dp 3 /p. 



TABLE 38. Certain distributions in apparatus II. Bar. 76cm.; temp. i8C. 



1 Ions under radiation not lost by exhaustion. 



