Experimental Researches in Electricity. 351 



conform fully to the standard. The attractions and repul- 

 sions due to a state of tension are readily exhibited ; the 

 evolution of heat has been distinctly indicated ; magnetic 

 effects led to the original discovery of this form of electri- 

 city ; chemical decompositions have been effected by M. 

 Pixii and M. Hatchette, after repeated failures on Faraday's 

 part ; physiological effects have been produced ; and the 

 feeble spark at first obtained has since been varied and 

 strengthened by Nobili, Antinori, and others, so as to 

 leave no doubt of its identity with the common electric 

 spark. 



At the period of the publication of the third series, in 

 January 1833, certain experimental effects had not been 

 produced with thermo-electricity, but prior to the publica- 

 tion of the collected researches in the volume now under 

 review, these vacancies had been supplied, so that with the 

 exception of the indications of tension, this form agrees 

 fully with the others. " Only those effects are weak or de- 

 ficient that depend upon a high degree of intensity : and if 

 common electricity be reduced in that quality to a similar 

 degree with the thermo-electricity, it can produce no effect 

 beyond the latter." 



The extraordinary physiological effects produced by the 

 gymnotus and torpedo, are well known to depend on the 

 power of evolving electricity, on contact, possessed by these 

 singular animals ; and relative to the identity of animal with 

 other forms of electricity, Faraday remarks, " After an ex- 

 amination of the experiments of Walsk, Ingenhouz, Caven- 

 dish, Sir H. Davy, and Dr. Davy, no doubt remains on 

 my mind as to the identity of the electricity of the torpedo 

 with common and voltaic electricity : and I presume that 

 so little will remain on the minds of others, as to justify my 

 refraining from entering at length into the philosophical 

 proofs of that identity. The doubts raised by Sir H. 

 Davy have been removed by his brother, Dr. Davy : the 



