SCIENCE AT THE BEGINNING OF THE CENTURY 



and claimed that this proves the immateriality of heat. 

 Later on he added force to the argument by proving, in 

 refutation of the experiments of Bowditch, that no body 

 either gains or loses weight in virtue of being heated 

 or cooled. He thought it proved that heat is only a 

 mode of motion. 



But contemporary judgment, while it listened respect- 

 fully to Rumford, was little minded to accept his ver- 

 dict. The cherished beliefs of a generation are not to 

 be put down with a single blow. Where many minds 

 have a similar drift, however, the first blow may precip- 

 itate a general conflict ; and so it was here. Young 

 Humphry Davy had duplicated Rumford's experiments, 

 and reached similar conclusions; and soon others fell 

 into line. Then, in 1800, Dr. Thomas Young" Phe- 

 nomenon Young" they called him at Cambridge, because 

 he was reputed to know everything took up the cud- 

 gels for the vibratory theory of light, and it began to 

 be clear that the two " imponderables," heat and light, 

 must stand or fall together ; but no one as yet made a 

 claim against the fluidity of electricity. 



But before this speculative controversy over the nat- 

 ure of the "imponderables" had made more than a fair 

 beginning, in the last year of the century, a discovery 

 was announced which gave a new impetus to physical 

 science, and for the moment turned the current of spec- 

 ulation into another channel. The inventor was the 

 Italian scientist Volta ; his invention, the apparatus to 

 be known in future as the voltaic pile the basis of the 

 galvanic battery. Ten years earlier Galvani had discov- 

 ered that metals placed in contact have the power to 

 excite contraction in the muscles of animals apparently 

 dead. Working along lines suggested by this discovery, 



27 



