28 PROCEEDINGS OP THE AMERICAN ACADEMY 



velocity of the earth in its orbit, and on the 21st of September 

 subtracted. On the 22d of December it would have no effect. Our 

 deflection on March 22d, then, should be about SD VoJ on December 

 22d, ^o o ; and on September 21st, 27W 



Of course, in actually taking observations, it is necessary to use 

 all six of the plates variously grouped and variously electrified, in 

 order to get rid of accidental phenomena. 



Even then the accidental phenomena frequently mask that for 

 which we are searching, and it is only from the discussion of a con- 

 siderable series of observations that results of value are obtained. 



I began my observations last September, and have continued 

 them at intervals since. The results observed are of the order of 

 magnitude predicted, and vary, as expected, with the season of 

 the year. 



If, continued until next September, the cycle is complete, I 

 shall feel even more sure of having discovered the phenomenon for 

 which I am searching, and of showing that the motion of the ether 

 possesses, both qualitatively and quantitatively, the properties of 

 an electric current, — that an electric current is a bodily f one ard 

 motion, of that same ether whose undulations we call light. 



