40 CONDENSATION OF VAPOR AS INDUCED BY NUCLEI AND IONS. 



As far as 11=1,500,000 nuclei per cubic centimeter, this curve would 

 still lie below the curve for the small apparatus. It then crosses and 

 passes beyond it to a limit of over 7,000,000 nuclei, instead of 4,000,000 

 nuclei per cubic centimeter, estimated for the small fog chamber, No. 3. 

 It is difficult, of course, without an actual measurement of aperture, to 

 come to a conclusion as to the order of mere colors, but the possibility 

 of reaching 10,000,000 nuclei per cubic centimeter does not now seem out 

 of the question. The probability that the initial white fogs seen with 

 ordinary light may be resolved with sufficient clearness for measurement 

 when monochromatic light is used, has already been suggested. One may 

 notice, however, in conclusion, that even in case of the extreme green, the 

 diameter of particle would still be over twice the wave-length of light. 



