HYPOTHESIS OF TWO FLUIDS. 425 



nomena of electrical attractions in a singularly 

 gratuitous manner. They say that when an 

 electrified glass tube, or stick of wax, is brought 

 near to light bodies, it communicates to them 

 the opposite electricity from its own ; and that 

 they are brought together by the mutual attrac- 

 tion of the two electricities for each other that 

 when they touch the excited electric, they ac- 

 quire the same kind of electricity which it has, 

 and consequently are repelled. (Thomson on 

 Heat and Electricity, p. 362.) It might as well 

 be said, that liquid metals attract the same 

 metals when solid, because they are in opposite 

 states of electricity ; or that the attraction of the 

 living body by frozen mercury is owing to the 

 combination of the former with positive, and the 

 latter with negative electricity ; and that the 

 effect is produced by the mutual affinity of the 

 two fluids : whereas I have proved that the at- 

 traction of frozen mercury, and other cold metals, 

 for the living body is in proportion to their 

 affinity for caloric, which is plus in the one, and 

 minus in the other; and that all such pheno- 

 mena are owing to the attraction of caloric and 

 electricity for ponderable matter. 



The whole train of Dr. Thomson's reasoning 

 in favour of two fluids is founded on groundless 

 assumptions. 1. That there is no attraction be- 

 tween electricity and ponderable matter: 2. that 

 there is an attraction between positive and negative 



