. Sharpies on some forms of Vie Gaha 



nic Batle. 



\\ . — rontrihuthns to Physirs in 

 ■->. XrAoo/.-No. 1. ByS. P. Shai: 



'n.i-'V.i 



On some forms of tfw G.ilr,n,:r / 





making some experiiiK'ht. ;,^ : • 





; .:ice in the ordinary bichromate battery. ;iih1 would he 

 .\ renewed. 



■ s occasion to use a battery, a few days after, 1 tried 



\Ture with such satisfactory results tliat it seemed desi- 



riille that the subject should be more fully investigated. The 



electro-motive force and internal resistance of the battery were 



therefore determined. 



The apparatus used was one of Poggendorffs rheostats, which 

 ^as furnished with sixteen meters of German silver wire, the 

 Instance of this being but little affected by changes of tempera- 

 ^^^\ ^J means of clamps, any number of centimeters of wire 

 could be introduced into the circuit When the needle of the 

 galvanometer was deflected to forty or fifty degrees a change of 

 one centimeter in the length of the resistance could be readd^' 

 ^^D- The galvanometer was an ordinary one in which the cod 

 ^as replaced by a broad, thick, copper band, passing once 

 ^und and close to the needle, which was suspended by a fila- 

 ment of silk and so adjusted that it was at the zero of the scale 

 ^nen it came to rest in the meridian. 



An order to determine the internal resistance, I made use of 

 wo elements of the same construction, which could be thrown 

 jnto the circuit either singly, or side by side. I found when all 

 my connections were bright, that there was no appreciable dif- 

 ference between the two elements, that is, either element when 

 connwjted with the galvanometer would deflect it the same 

 'inmberofdegreea ^ ^ ^^ 



l&e zincs were about four inches high, and two and a halt 

 ^'^^J,?tenial diameter, with a slit in one side. The porous 

 ^^ hlled the internal space almost entirely. The carbons 



