330 VOLTAIC ELECTRICITY. [SECT. xxix. 



SECTION XXIX. 



Voltaic Electricity The Voltaic Battery Intensity Quantity Comparison 

 of the Electricity of Tension with Electricity in Motion Luminous Effects 

 Decomposition of Water Formation of Crystals by Voltaic Electricity 

 Electrical Fish. 



VOLTAIC electricity is of that peculiar kind which is elicited 

 by the force of chemical action. It is connected with one 

 of the most brilliant periods of British science, from the 

 splendid discoveries to which it led Sir Humphry Davy ; 

 and it has acquired additional interest since the discovery of 

 the reciprocal action of Voltaic and magnetic currents, which 

 has proved that magnetism is only an effect of electricity, and 

 that it has no existence as a distinct or separate principle. 

 Consequently Voltaic electricity, as immediately connected 

 with the theory of the earth and planets, forms a part of the 

 physical account of their nature. 



In 1790, while Galvani, Professor of Anatomy in Bologna, 

 was making experiments on electricity, he was surprised to 

 see convulsive motions in the limbs of a dead frog accidentally 

 lying near the machine during an electrical discharge. Though 

 a similar action had been noticed long before his time, he was 

 so much struck with this singular phenomenon, that he 

 examined all the circumstances carefully, and at length 

 found that convulsions take place when the nerve and muscle 

 of a frog are connected by a metallic conductor. This excited 

 the attention of all Europe ; and it was not long before 

 Professor Volta of Pavia showed that the mere contact of 

 different bodies is sufficient to disturb electrical equilibrium, 

 and that a current of electricity flows in one direction through 

 a circuit of three conducting substances. From this he was 

 led, by acute reasoning and experiment, to the construction 



