Galvanism i from Galvani to Ohm. 83 



ductors which oppose its course, and makes a perforation 

 precisely of the same description as would have been made 

 by something which had need of place for its passage. We 

 often observe this when electric jars are broken by an over- 

 charge, or when the electric shock is passed through a number 

 of cards, etc. We may therefore, at least with some proba- 

 bility, imagine caloric and the electricities to be matter, 

 destitute of gravitation, but possessing affinity to gravitating 

 bodies. When they are not confined by these affinities, they 

 tend to place themselves in equilibrium in the universe. The ^ 

 suns destroy at every moment this equilibrium, and they send 

 the re-united electricities in the form of luminous rays towards 

 the planetary bodies, upon the surface of which the rays, being 

 arrested, manifest themselves as caloric ; and this last in its 

 turn, during the time required to replace it in equilibrium in 

 the universe, supports the chemical activity of organic and 

 inorganic nature." 



It was scarcely to be expected that anything so speculative 

 as Berzelius' electric conception of chemical combination 

 would be confirmed in all particulars by subsequent discovery ; 

 and, as a matter of fact, it did not as a coherent theory survive 

 the lifetime of its author. But some of its ideas have 

 persisted, and among them the conviction which lies at its 

 foundation, that chemical affinities are, in the last resort, of * 

 electrical origin. 



While the attention of chemists was for long directed to 

 the theory of Berzelius, the interest of electricians was 

 diverted from it by a discovery of the first magnitude in a 

 different region. 



That a relation of some land subsists between electricity 

 and magnetism had been suspected by the philosophers of the 

 eighteenth century. The suspicion was based in part on some 

 curious effects produced by lightning, of a kind which may be 

 illustrated by a paper published in the Philosophical Transactions 

 in 1735.* A tradesman of Wakefield, we are told, "having put 



*Phil. Trans, xxxix (1735), p. 74. 

 G 2 



