100 



mass of fluid. Whatever cireumstauce favours the decomposition 

 of the water, will also increase the power of the voltaic arrange- 

 ment. Conformably to these views we find that all liquids whose 

 component parts go to the same pole are non-conductors of voltaic 

 electricity. A given section of a liquid is capable of conducting 

 only a limited quantity of electric influence. It was also found by 

 experiment that when sulphuric acid was employed, the quantity 

 of electro-magnetic action in the connecting wire is exactly propor- 

 tional to the quantity of water decomposed in the liquid part of 

 the circuit. This quantity is, within certain limits, inversely pro- 

 portional to the square root of the distance between the plates. 



In the second part of this paper the author enters upon an investi- 

 gation of the fundamental principle and laws of action of the voltaic 

 battery. He calls in question the truth of the common theories of 

 galvanism, which are founded on the supposition of electricity being 

 accumulated in the poles of the battery before the circuit is completed, 

 and of its actual transfer and continued circulation through the entire 

 course of the circuit. In order to analyse the effect of a single gal- 

 vanic circle, the author made the following experiments. A com- 

 pound plate of zinc and copper soldered together was cemented into 

 a trough, and two single plates of copper of the same size were ce- 

 mented, one on each side of the former plate, into the same trough, 

 so as to form a cell on each side of it ; and the cells were filled with 

 dilute acid. On connecting the extreme copper plates by metallic 

 wires with a delicate torsion galvanometer, a certain deflection of the 

 needle was produced. When two compound plates were placed be- 

 tween the terminal copper plates, the deflection was twice as great ; 

 when three were employed, it was three times as great, and so on. 

 It is thence inferred that the voltaic effects of two batteries of the 

 same length, and with plates of the same size, are directly propor- 

 tional to the number of plates. By prosecuting this inquiry, the 

 author finds that, within certain limits, the voltaic energies of two 

 batteries, consisting of plates of the same size, and placed at equal 

 distances, but differing in number, are very nearly proportional to the 

 square root of the number of plates. This result was deduced both 

 from the quantity of water decomposed by the apparatus, estimated 

 by the quantity of hydrogen disengaged, and also by the electro- 

 magnetic effects, as measured by the torsion galvanometer. But 

 when the number of plates is greatly extended, the above law of in- 

 crease is no longer observed, the effect being less than in proportion 

 to the square root of the number. By continuing to increase the 

 number of plates, we at length reach a limit beyond which there is 

 no increase of effect, but rather a diminution. So that if the voltaic 

 power were represented by the ordinates of a curve of which the 

 abscissa denoted the number of plates, the curve, from being at first 

 a parabola, would afterwards deviate into a form approaching to that 

 of an ellipse. 



In the third part of the paper the author relates experiments which 

 prove that every part of the galvanic circuit conducts the same quan- 

 tity of electricity, whatever be the material, whether solid or fluid, 



