FRANKLIN'S KITE EXPERIMENT. 



743 



would dive even when high in air. Once we kept the kite aloft 

 from the forenoon until late at night, but that was something 

 unusual. 



Passing now over six years in which we had been busy meas- 

 uring the electrifica- 

 tion of the air under 

 all conditions, and dis- 

 covering, for example, 

 that a snowstorm was 

 almost identical with 

 a thunderstorm in its 

 tremendous electrical 

 changes, we come to 

 the year 1891, when we 

 again flew kites for the 



100 



-1-50 



Volts 



50 



100 



4.45 P.M. 5 



30 



45 



:tor T Kite 



Collect 

 June 30, 1891. 



ELECTRICAL POTENTIAL OF THE AIR. Small collector about 

 fifteen feet from ground ; kite about five hundred feet 

 from ground. 



purpose of electrically 



exploring the air. Our 



experiments at the top 



of the Washington Monument in 1885 and 1886 (especially those 



during severe thunderstorms, when we obtained potentials as 



high as three and four thousand volts just before the lightning), 



MULTIPLE QUADRANT ELECTROMETER, JULY, 1892. Blue Hill Observatory. 



had given us an insight into the strains and stresses in the air, 

 and taught us what to expect at such times. There was still 

 little improvement in the kite, but much better electrical appa- 



