SECT, xxxv.] IDENTITY OF THE ELECTKICITIES. 383 



have long been known, but the world ia indebted to Dr. 

 Faraday for the wonderful discovery of the heating power 

 of the magnetic fluid : there is no indication of heat either 

 from the animal or thermo electricities. All kinds of electri- 

 city have strong magnetic powers, those of the Voltaic fluid 

 are highly exalted, and the existence of the magneto and 

 thermo electricities was discovered by their magnetic in- 

 fluence alone. The needle has been deflected by all in the 

 same manner, and magnets have been made by all according 

 to the same laws. Ordinary electricity was long supposed 

 incapable of deflecting the needle : M. Colladon and Dr. 

 Faraday however have proved that, in this respect also, 

 ordinary electricity agrees with Voltaic, but that time must 

 be allowed for its action. It deflected the needle, whether 

 the current was sent through rarefied air, water, or wire. 

 Numerous chemical decompositions have been effected by 

 ordinary and Voltaic electricity, according to the same laws 

 and modes of arrangement. Dr. Davy decomposed water 

 by the electricity of the torpedo Dr. Faraday accom- 

 plished its decomposition, and Dr. Ritchie its composition, 

 by means of magnetic action : and M. Botto of Turin has 

 shown the chemical effects of the thermo-electricity in the 

 decomposition of water, and some other substances. The 

 electric and galvanic shock, the flash in the eyes, and the 

 sensation on the tongue, are well known. All these effects 

 are produced by magneto-electricity, even to a painful 

 degree. The torpedo and gymnotus electricus give severe 

 shocks, and the limbs of a frog have been convulsed by 

 thermo-electricity. The last point of comparison is the 

 spark, which is common to the ordinary Voltaic and mag- 

 netic fluids : and Professor Linari, of Siena, has very lately 

 obtained both the direct and induced sparks from the tor- 

 pedo, proving that in this respect animal electricity does 

 not differ from the others. Indeed, the conclusion drawn 

 by Dr. Faraday is that the five kinds of electricity are 

 identical, and that the differences of intensity and quantity 



