294 Recent Studies in Gravitation. [Feb. 23, 



to Faraday, are leading, I believe, to the identification of electrifica- 

 tion and chemical separation, to the identification of electric with 

 chemical energy. 



But gravitation still stands alone. The isolation which Faraday 

 sought to break down is still complete. Yet the work I have been 

 describing is not all failure. We at least know something in 

 knowing what qualities gravitation does not possess, and when the 

 time shall come for explanation all these laborious and, at first 

 sight, useless experiments will take their place in the foundation on 

 which that explanation will be built. 



[J. H. P.] 



