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XXIX. Account of the Refults of fame comparative Experi- 

 ments made tu'ith the Tejlcrinn Ele6lr'ical Apparatus and 

 Folta's Mitallic Pile. By Van Marum and Pfaff. 

 Communicated to Profeffor VoLTA in a Letter dated No- 

 vember 1801. Abridged bv Luke Howard, Efq. Jro7n 

 Journal de Chimie by J. B. P"un Mons *. 



A 



PILE of 200 pairs of metals was conftnifted in the 

 ufual method of Volta. The metals employed were Dutch 

 three florin pieces of nearly i, inch in diameter, and corre- 

 fpondent pieces of zinc. The firll experiments were diretted 

 to chargino- the jars of a large battery containing 5' fquare 

 feet of coated furfxce a-piece. A Mngle jar was firft charged, 

 afterwards different numbers connefted, and fucceffively aug- 

 mented to 25. In fithe rll, and in each fucceeding experiment, 

 the charge was effected by mere contaA for as little time as 

 poffible with the pile. The difchargc in every cafe produced 

 a divergence of the sjold leaves in Eennet's ele(Sronieter, 

 amonnlintr to ths of an inch, which was alfo found to be 

 the degree of intenfity {ten/ion) of the pile itfelf. 



The whole coated furface of 137; f(]uare feet was next 

 charged, atfevcral times, bv a pile augmented at each charge. 

 With 40 pairs of metals, the divergence of the ele(9;rometer 

 was perceptible. Tiie increafcd divergence caufed by the 

 pile itfelt at each addition, was equally producible by the 

 battery when charged by it. No difference was perceived in 

 the effects of the negative and pofitive liates of the battery 

 in this refpeft. 



The fenfations producible by the difcharges under the laft- 

 mcntioned arrangements were as follow : 



Willi 20 pairs of metals, the palllige of eleftricity was fen- 

 fibly fell in buth hands, each being wetted, and grafping a 

 copper conductor of 2 inches diameter. Sixty pairs affedted 

 the elbows. With 200, ftrong iliocks were received, extend- 

 inc to the flioulders. 'I'hey concluded that the force of the 

 battery in itiis relpcct was in all cafes only half that of the 

 pile; which indeed was to be f'xpected. 



They next proceeiled to a comparative examination of the 

 clnr'^rt; conimunii able by momentary contact of the battery 

 ^vitll the coiulu(i'.tor of an clciMrical ulals plate aj)paratus of 

 31 inches diameter. Precautions were ulVd to fecure the 

 conductor from receiving more than a momentary charge 

 from ibe [)laie. It was found, by repeated trials, that lix 



■ CV." iTiui.icdtcd \'V Mr. Howard. 



VoL.Xn. No. 46. L repetitions 



