IV ADVERTISEMENT. 



Fiually the importance of conelating this variation of nm-lear diameter with the 

 fclectrioal activity of the water nucleus is insisted on, with a view to its possible 

 application to atmospheric electricity. 



In accordance with the rule adopted by the Smithsonian Institution, the work 

 has been submitted foi- examination to a Committee consisting of Professor Wilder 

 D. Bancroft, of Cornell University, and Professor Edgar F. Smith, of the University 

 of Pennsylvania, and, having been recommended for publication, it is herewith 

 presente<l in the series of Contributions to Knowledge. 



S. P. LANGLEY, 



SECRETARY. 



Smithsonian Institution, 



Washington, January, 1903. 



