•_>U RECENT STUDIES IN GRAVITATION. 



But this unlikeness, this independence of gravitation of any quality 

 but mass, bars the way to any explanation of its nature. 



The dependence of electric forces on the medium, one of Faraday's 

 grand discoveries forever associated with the Royal Institution, was 

 the firsl step which led on to the electromagnetic theory of light, now 

 so splendidly illustrated by Hertz's electromagnetic waves. The 

 quantitative laws of electrolysis, again (\\\^ to Faraday, are leading, I 

 believe, to the identification of electrification and chemical separation— 

 to the identification of electric with chemical energj^. 



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 gravitat ion does not possess, and when the time shall come 

 for explanation all these laborious and. at first sight, useless experi- 

 ments will take their place in the foundation on which that explanation 

 will be built. 



