A CONTINUOUS RECORD OF ATMOSPHERIC NUCLEATION. 

 Third Series. — ^^ = 24°; barom. = 75.08 cm.; c5/ = 2"'. 



95 



«' and S' computed froin subsidence and time. 



To compare the new observations with the older ones above, it is con- 

 venient to lay off the aperture, s, in terms of the order of the exhaustion, z, as 

 has been done in the charts, figtares 12 and 13. The following peculiarities are 

 observed: Below the g-b-p coronas (5 = 6 to 6.5 cm.) the general slope of all the 

 curves is nearly the same. Above these coronas, the older results obtained with 

 the plug valve correspond to a decidedly steeper slope than the new results. 

 Curiously enough, therefore, a greater number of exhaustions are required in 

 the case of the instantaneous valve to pass from a given corona to a given 

 succeeding corona than in the case of the stopcock. The instantaneous valve 

 thus removes a smaller relative number of nuclei per exhaustion than does the 

 stopcock, so long as fresh nviclei or great numbers are in question. Subsidence 

 of fog for the very fine particles here in question need not be considered in 

 explanation. In fact, the recent work is even more rapid than the old. 



35. Growth of nuclei. — The simplest way of accounting for this result is to 

 assume that there is a continual growth of nuclei in the interval between the 

 observations, whereby those of extreme smallness come first within the range 

 of action of the instantaneotis valve. The excess of available nuclei obtained 



