CALORIC AND ELECTRICITY. 453 



rest. M. Becquerel found, that when one end 

 of the multiplying wire was heated and brought 

 in contact with the other end, the needle was 

 deflected. Hundreds of similar experiments 

 might be adduced, all of which demonstrate the 

 agency of caloric in producing magnetism, where 

 there is no sign whatever of electric tension; 

 and that the magnetic needle is a true test of 

 the smallest quantities of caloric that have ever 

 been measured. 



Some of the most delicate experiments on re- 

 cord were performed by Dr. Locke of Cincinnati. 

 By interposing one quarter of a grain of anti- 

 mony between the two copper wires of a mul- 

 tiplier, and applying the warmth of his finger, 

 the needle was deflected 22. In another ex- 

 periment, one of the copper wires was laid upon 

 the other, without the interposition of any other 

 metal, and the warmth of the hand applied as 

 before, when the needle was deflected 6. The 

 same results were obtained by substituting the 

 warmth of the breath instead of that of the hand. 

 The temperature of the room in which the ex- 

 periments were made was 65. F. (American 

 Journal of Science, April, 1834.) 



But the most decisive proof that caloric and 

 electricity are only modifications of one and the 

 same agent is, that they are mutually convertible 

 into each other ; and that the electric fluid ob- 

 tained from a permanent natural magnet, fuses, 

 volatilizes, and ignites charcoal, metals, and 



