Laws of the Elementary Voltaic Battery. 39 



Art. II. — Experimental Enquiry into some of the Laws of the Ele- 

 mentary Voltaic Battery ; by William B. Rogers, Prof. Nat. 

 Philosophy and Chemistry in William and Mary College, and 

 Henry D. Rogers, F. G. S. of Lond. Sic. 



We send for publication In your valuable Journal, a series of ex- 

 periments made upon the voltaic battery for the purpose of investi- 

 gating the circumstances which principally modify its action. They 

 all have a direct reference to the most efficient construction and 

 mode of employing this powerful engine of research, while some of 

 them, moreover, lead immediately to conclusions respecting its laws, 

 very different from those of Ritchie and other celebrated experi- 

 menters on the subject. In the hope therefore that the observations 

 which we are about to record, will be found sufficiently new and im- 

 portant to provoke a more thorough investigation of this portion of 

 the field of electrical science, we beg leave to present our experi- 

 ments in the order in which they were made, with some brief re- 

 marks upon the conclusions to which they lead. 



For the sake of greater accuracy, all our experiments were made 

 upon the battery in its most elementary form, consisting of a single 

 pair of zinc and copper plates in the shape of long slips an inch wide, 

 and from four to twelve inches long. The slips were graduated by 

 transverse lines into inches and parts. To the upper end of each 

 slip a copper wire, always of the same length, was carefully soldered, 

 the other extremity of the wire being amalgamated and dipped into 

 the cup of the galvanometer. The slips were placed parallel to each 

 other, and generally an inch and a quarter apart. To secure them 

 in this position, and at the same time to be enabled to immerse them 

 to the various depths required, they were supported in two parallel 

 slits in the cover of the vessel containing the acid solution, and ad- 

 justed by sliding up or down to the degree of immersion desired. 



The galvanometer, which was one of extreme delicacy, was con- 

 structed on a large scale, and with some modifications of the original 

 invention, which we believe to add to its accuracy as an instrument 

 of research. Being moreover simple in its parts, it can readily be 

 constructed by any experimenter, and we therefore subjoin a brief 

 description and drawing. 



Fig. 1, represents the instrument adjusted for use. A and B are 

 circles of well seasoned wood, 12 inches in diameter, connected by 



