A CONTINUOUS RECORD OF ATMOSPHERIC NUCLEATION. 



209 



19. The high nucleation of March, 1904 (charts 37, 38, 39), is in distinct 

 contrast to the relatively low nucleation of March, 1903. This is true in like 

 measure for April, May, and even June. In 1904, the winter nucleations are in 

 all cases very gradually replaced by the low summer nucleations. The sweep 

 of temperature from March 1-15 is in very full accord with the changes of 

 nucleation. Remarkably high rain minima occur on March 3, 7, 18, 22, and 

 the same is true of the snow minima on March 11, 15, 18, and of the Sunday 

 minima on March 6, 13, 20, 27. On the 14th there is a cloud effect. Toward the 

 end of the month temperature correspondence ceases and the nucleation remains 

 high, in spite of weather much above freezing. 



h Mail K 



SO Ti n « w 



ClIART.S 40, 41, 42, 43. 



20. The first period of nucleation, beginning with the rain of April i 

 (charts 39, 40, 41) and terminating in the rain of April 7, partakes of the rela- 

 tively high character for the season already instanced. It is possibly referable 

 to the corresponding sweep of temperature which approaches freezing on April 

 4, supposing that the nucleation due to fall of temperature outlasts the latter. 

 The period from April 10-18 is less pronounced, but high nucleation corresponds 

 to the moist snows on April 14 and 16. The night observations betray nothing 

 unusual. The final cycle of the month from April 19 to the very low minimum 



