426 HYPOTHESIS OF TWO FLUIDS. 



electricity : 3. that matter does not repel matter: 

 and, 4. that nothing but the pressure of the am- 

 bient atmosphere prevents the escape of electricity 

 from bodies. (Idem p. 424.) Feeling some doubt 

 in regard to the last position, he elsewhere 

 speaks of "the unknown cause which prevents 

 it from leaving them." (Page 431.) Dr. Thom- 

 son maintains, that " matter does not repel matter, 

 because, in the motions of the heavenly bodies, 

 no such repulsion has ever been observed," 

 from which it would seem that he denies the 

 existence of a repulsive agency in nature. Hav- 

 ing assumed the above premises, he adds, " if 

 matter does not repel matter, and if there does 

 not exist any attraction or affinity between elec- 

 tricity and matter, then the Franklinian theory 

 of positive and negative electricity cannot be 

 correct."* (Page 425, on Heat and Electricity.) 



* It is somewhat remarkable, that ^Espinus, who first gave to 

 Franklin's theory a mathematical form, should have regarded it 

 as incapable of explaining the phenomena of electrical attrac- 

 tions and repulsions, without also admitting that " matter repels 

 matter." What does he mean by this ? Has it not been recog- 

 nized by all the most distinguished writers on Natural Philo- 

 sophy, from Newton to Laplace, that all matter is endowed with 

 a power of repulsion as well as attraction ? And I have proved 

 that both these effects are produced by one and the same active 

 principle, which surrounds the particles of all bodies which, in 

 certain proportions maintains their solidity, in others their liqui- 

 dity, vaporization, and gasefaction and without which there 

 could be no contraction and expansion of matter, consequently 

 no motion. 



