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XLVII. A Memoir on some new 'Modifications nf Galvanic Ap- 

 paratus, with Observations in Support "f his Theory of Gal- 

 vanism. By R. Hare, M.t). Projessor of Chemislry in the 

 University of Pennsylvania *. 



X HAD observed thnt the ignition pioducrd by one or tuo gal- 

 vanic pairs attained its highest intensity, almost as soon as they 

 were covered by the acid used to excite theui, and ceased soon 

 afterwards ; although the action of the acid should have increased 

 during the interim. I had also remarked, in using an apjjaratus 

 of three hundred pairs of small plates, that a platina wire of Num- 

 ber 16, placed in the circuit, was fused in consequence of a con- 

 struction which enabled nie to plunge them all nearly at the same 

 time. It was therefore conceived, that the maximum of effect 

 in Voltaic apparatus of extensive series had never been attained. 

 The plates are generally arranged in distinct troughs rarely con- 

 taining more than twenty pairs. Those of the great apparatus 

 of the Royal Institution^ employed by Sir H. Davy, had only ten 

 pairs in each. There were one hundred such to be successively 

 placed in the acid, and the whole coimected ere the poles could 

 act. Consequently the effect which arises immediately after im- 

 mersion, would be lost in the troughs first arranged, before it 

 could be produced in the last ; and no effort appears to have been 

 made to take advantage of this transient accumulation of power, 

 either in using that magnificent combination, or in any other of 

 which I have read. In order to observe the consequence of si- 

 multaneous immersion with a series sufficiently numerous to test 

 the correctness of my expectations, a galvanic apparatus of eighty 

 concentric coils of copper and zinc, was so suspended by a beam 

 and levers, as that they might be made to descend into, or rise 

 out of the acid in an instant. The zinc sheets were about nine 

 inches by six, the copper fourteen by six ; more of this metal 

 being necessary, as in every coil it was made to commence within 

 the zinc, and completely to surround it without. The sheets 

 were coiled so as not to leave between them an interstice wider 

 than a quarter of an inch. Each coil is in diameter about tvvo 

 inches and a hair, so that all may descend freelv into eighty glass 

 jars two inches and three quarters diameter inside, and eight 

 inches high, duly stationed to receive them. 



My apparatus being thus arranged, two small lead pipes were 

 severally soldered to each pole, and a piece of charcoal about a 

 quarter of an inch thick, and an inch and a half long, tapering 

 a little at each extremity, had these severally inserted into the 



* Communicated by the Author. 



hollow 



