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nation, he contrived an apparatus, which he designates by the name 

 of the dissected battery, and which consists of ten cylindrical glass 

 cells, capable of holding the fluid electrolytes, in which two plates 

 of metal are immersed ; each plate communicating below, by means 

 of a separate wire, which is made to perforate a glass stopper closing 

 the bottom of the cell, with a small quantity of mercury, contained 

 in a separate cup underneath the stopper, and with which electric 

 communications may be made at pleasure through other wires passing 

 out of the vessel on each side. The active elements of the circuit, 

 which were adopted as standards of comparison, were, for the me- 

 tals, plates of platinum and amalgamated zinc three inches in length 

 by one in breadth; and for the electrolyte, water acidulated with 

 sulphuric acid, in the proportion of 100 parts by volume of the for- 

 mer to 2*25 of the latter - } this degree of dilution (giving a spe- 

 cific gravity of 1*0275,) being adopted, in order to connect the au- 

 thor's experiments with those of Mr. Faraday. 



This dilute acid exerts scarcely any local action on amalgamated 

 zinc ; because the surface of the metal becomes covered with bub- 

 bles of hydrogen gas, which adhere strongly to it; and this force 

 of heterogeneous adhesion appears to have an important influence 

 on the phenomena both of local and of current affinity, and soon 

 puts a stop to the decomposition of the water by the zinc. When 

 a small quantity of nitric acid is added to the acidulated water, the 

 same plate which in the former experiment resisted the action of 

 the diluted sulphuric acid, is, in a few hours, entirely dissolved, 

 without the extrication of any gaseous matter. This result is ex- 

 plained by the author on the supposition that the elements of the 

 nitric acid enter into combination with the hydrogen as it is evolved, 

 and that the opposing attraction of this latter substance is thus re- 

 moved. The author finds, in like manner, that nascent hydrogen 

 deoxidates copper, and precipitates it from its solutions upon the 

 negative plate of the voltaic circuit. 



A series of experiments performed with the dissected battery is 

 next described ; illustrating, in a striking manner, the difference of 

 effects with relation to the quantity and the intensity of the electric 

 current, consequent on the different modes of connecting the ele- 

 ments of the battery : the former property being chiefly exhibited 

 when the plates of the respective metals are united together so as 

 to constitute a single pair ; and the latter being exalted when the 

 separate pairs are combined in alternate series. The influence of 

 different modifications of these arrangements, and the effects of the 

 interposition of pairs in the reverse order, operating as causes of 

 retardation, are next inquired into. 



In the course of these researches, the author, being struck with 

 the great extent of negative metallic surface over which the deoxi- 

 dating influence of the positive metal appeared to manifest itself, 

 as is shown more especially in the cases where a large sheet of cop- 

 per is protected from corrosion by a piece of zinc or iron of com- 

 paratively very small dimensions, was induced to institute a more 

 careful examination of the circumstances attending this class of phe- 



