IIO NUCLEATION OF THE UNCONTAMINATED ATMOSPHERE. 



data are constructed for rapid inspection in figure 102, of Chapter 

 V (lower curve). The initial (high) observations marked with a circle 

 were made with the same apparatus in Providence. The curve as a 

 whole shows two well-defined undulations, one extending from 

 December into the beginning of January and the other from this 

 epoch to the beginning of April. After this the data are scattering. 

 Fur ther discussion will be appropriately given in connection with the 

 corresponding data found at Providence and detailed in the next 

 chapter. 



82. Average monthly nucleations at Block Island. Table 59, below, 

 contains the monthly average of the number of nuclei in the atmos- 

 phere of Block Island in thousands per cubic centimeter. The data 

 are reproduced in figure 93. The curve contains definite indica- 

 tions of a maximum in December practically coinciding with those 

 found in the two preceding years in Providence, as suggested by the 

 dotted line. After January, however, the enormous increment of 

 nucleatiou which characterizes the February observations appears. 

 This is the feature of the present results, and the effects continue with 

 general moderations during March and April ; for the nucleation of 

 March actually exceeds that of December, while April is not much 

 below January, showing, therefore, that very unusual conditions pre- 

 vail in the atmosphere. 



To interpret this curve, /. e., to discriminate between terrestrial and 

 cosmical interferences with the atmosphere, it will be necessary to 

 compare it with the corresponding monthly distribution of the meteoro- 

 logical constants of the atmosphere. This will be appropriately done 

 in Chapter V, section 5, in connection with the other data there given. 



TABLE 59. Average monthly nucleations at Block Island, 1904-5. 



* November, 1904 .................................... <C 7-o 



December, 1904 .... ................................. 7. i 



January, 1905 ...................................... 5.4 



February, 1905 ...................................... 13.9 



March, 1905 ...................................... 7.9 



April, 1905 ...................................... 5.0 



t May, 1905 ...................................... < 5.0 



* November 21-30, only. Average datum therefore too high. 

 t May 1-3, only. Average datum therefore much too high. 



