I06 NUCLEATION OF THE UNCONTAMINATED ATMOSPHERE. 



as also on the 5th and i6th. On the 3d the nuclei seem to have been 

 completely wiped out by rain, and we get no more till the sun shines 

 next day. From the i2th to the [6th the nucleation lags behind the 

 other curves in recuperating, and again on the 2ist and 27th. As 

 is often the case for low values, the nucleation does not follow the 

 other curves on January 19. During the last days of the month the 

 behavior of the nuclei is quite unusual, although the snow on those 

 days is light and dry. 



FIG. 93. Chart showing the average daily nucleations at Block Island, in hundreds 

 per cubic centimeter, from December to May, 1904-5. 



FIG. 94. Location of the stations at Providence and at Block Island. 



