A CONTINUOUS RECORD OF ATMOSPHERIC NUCLEATION. 



117 



TABLE 4.— FIRST SERIES OF NEGATIVES MEASURED FOR J AND);, m = 4.7 X Io-^ 

 ^fn = 2.11 n' /icm''^io''. /= 20' to TiO'. Sp= i-j cm. 



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

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

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

 uated, and the fog particles had in many iiistances 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 atid on using the in- 

 stantaneous valve described above. 



Inferences. 



18. Precipitation per cubic centimeter. — The precipitation, m, computed 

 from the plates Nos. 4, 5, and 6, for instance, would be 57 X 10"'', 4.8 X lo"*^, 

 5.7 X 10"" grams per cubic centimeter, respectively. In the first case the deposit 

 is excessive, probably due toeddy ctn-rents, 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. 



