A CONTINUOUS RECORD OF ATMOSPHERIC NUCLEATION. 



117 



TABLE 4. FIRST SERIES OF NEGATIVES MEASURED FOR d AND n. m = 4 . 7 X io- 6 . 



frn = 2. ii n'/tcm" 3 io 6 . t = 20* to 30'. <5p=ijcm. 



The results with fog particles condensed on nuclei of atmospheric air (table 

 6) and photographed by a small kodak were not very successful, due to second- 

 ary causes. In the small vessel used, the tendency to evaporation was accent- 

 uated, and the fog particles had in many instances evaporated before the 

 photograph could be taken. Hence d was not measured. 



In table 7 the chief purpose was a comparison of the precipitates obtained 

 when using an ordinary stopcock to effect the exhaustion and on using |the in- 

 stantaneous valve described above, 



Inferences. 



1 8. Precipitation per cubic centimeter. -The precipitation, m, computed 

 from the plates Nos. 4, 5, and 6, for instance, would be 57 X io" 6 , 4.8 X io~ 6 , 

 5.7 X io ~ 6 grams per cubic centimeter, respectively. In the first case the deposit 

 is excessive, probably due to eddy currents, in the second nearly correct, in the 

 third too large. It is preferable, however, to compare the values of d and n 

 obtained from the photographs directly with the data from coronas. 



