48 LIFE AND WORK OF SIR JAGADIS C. BOSE 



phenomena which appear in course of his study of light, 

 and which he can thus not only experiment upon, but explain 

 with mathematical clearness. 



Contemporary with Fresnel, as mathematician of light, 

 was Ampere, the mathematician of electricity. He worked 

 out the laws of those mutual actions of currents which had 

 been discovered by the succession of brilliant experimentalists 

 up to Faraday. In thus rising from the experimental and 

 empirical level, and establishing Electro-dynamics as a 

 rational science, he naturally enough suggested that the 

 ether which carries the waves of light must also be the 

 vehicle of electric disturbances. But the testing of this 

 attractive hypothesis by experiment no easy matter was 

 next accomplished by Clerk Maxwell, who was rewarded by 

 the discovery that electrical disturbances travelled with the 

 same velocity as that of light a result concordant with 

 previous independent calculation of the speed of a current 

 through a perfectly conducting wire. That some intimate 

 correspondence must exist between electricity and light 

 could thus no longer be doubted. Maxwell's next step was 

 to reinterpret the familiar contrast of conductors and non- 

 conductors ; and now, instead of thinking the latter inert, 

 as scientific men had hitherto done (so that the reader may 

 be pardoned for perhaps still doing so), he reinterpreted 

 both together. The familiar copper wire is not a perfect 

 conductor, but has an appreciable resistance, of which Ohm 

 had already determined the simple law ; with progressive 

 loss of energy accordingly, which appears in the wire as 

 heating ; this raised to white heat gives us light as in an electric 

 lamp. The process of electric loss in production of heat, 

 Maxwell compared to what he observed when water is forced 

 through pipes, with friction and heat increasing as these 

 are narrowed ; and it is evident that since fluids are all 

 more or less imperfect (indeed water being a viscous fluid 

 compared with many others), the movement of the fluid 

 must sooner or later come to a stop, and all its energy 

 converted into heat. In short, then, the electrical 





