4 dole: chlorine content of rain water 



of chlorine, had a chlorine content of 2.9 parts per million. The 

 residue from a liter dried at 180°C. was 31 parts per million, only 

 a small part of which could be attributed to solution of the 

 bottles for the residue contained but 2.0 parts per million of 

 silica. 



Tho this content of chlorine can not be considered an average 

 because of the variable effect that wind-borne spray has on the 

 salt in the rain it serves as a contribution to the rather scanty 

 knowledge regarding the composition of rain water in the United 

 States. The above-mentioned chlorine, 2.9 parts per million, is 

 equivalent to about 5 parts of sea salt. With an annual rainfall 

 of 60 inches this is equivalent to a precipitation of 65 pounds of 

 salt per acre per annum. Figures quoted by Clarke^ for Barbados 

 are equivalent to 193 pounds and others range from 24 pounds in 

 England to 298 pounds in Ceylon. 



1 Clarke, F. W., The data of geochemistry: U. S. Geol. Survey, Bull. 491, p. 

 50. 1911. 



