40 Defcriftlon of a newly invented Galvanometer, 



without obferving any divergence of the gold leaves or any 

 peculiar tafte. 



Wlu-n the gold came into ahfolutc contact with the zinc 

 the tatte was mliantty percept ible, in the lame manner as 

 when an immediate connection is eftabliuV'd between zinc, 

 and iilver, by bringing- them into contact between the teeth 

 alter they have been properly difpofed in the mouth; but 

 [ could never perceive, when they were feniibly afunder, the 

 imallett effect, and therefore, after repeated fruitlefs attempts 

 to increafe the action by enlarging; the iurfaees of the metals 

 in contact with the mouth, laid the inftrument afide, as ufe- 

 lefs, except as a more delicate electrometer. 



As I attributed niv want of fuccefs not fo much to any 

 error either in the principle- or conltruetion of my inftrument, 

 as to the imallnefs of the galvanic charge, M. Voha had no 

 fooner made his pile known, than it occurred to me, that, as 

 a ftroHger charge miffHt now be obtained, the inltrument I 

 had conttructed' would certainly be affected by it, if the elec- 

 tric and geilvanic fluid p off effed, identity. 



My friend, Mr. Henry Lawfon, having conftru&ed a pile, 

 confiiting of 80 pieces of zinc, and as many of iilver, we 

 made the experiment together. The filver of the galvano- 

 meter was connected with the upper piece of the pile, which 

 was zinc, While the filver end of the pile was in contact with 

 the zinc of the galvanometer. The Hiding pieces BC were 

 then adjuftcd, and, at t lie diftance of i-^d of an inch from 

 each other, the gold leaves diverged : upon prefenting excited 

 gUfe they opened {till further, proving it to be that Hate called 

 plus, or pofitwe. 



We then reverfed the connection, making the lower or 

 zinc end oi the galvanometer join the upper or zinc end of 

 the pile, and the Iilver flip join the lower or iilver end of the 

 pile. In this cafe, excited glai's made the leaves to dole, 

 while excited feaiing-wax opened them further. 



When we made This trial of the galvanometer, the pile was 

 giving (hocks, thai were taken with a lenlation equal to what 

 would have been experienced from a charge of as much coated 

 furface of electricity as would, if difcharged through the gal- 

 vanometer, have torn and destroyed the gold leaves, while 

 by galvanifm they were only diverged equal to about i~4th 

 of an inch: even fealing-wax ilightly excited, prefented to 

 the inltrnment, kept the leaves in coniiant motion. 



Since that time 1 have performed a number of experiments 

 with Volta's pile ; indeed, I have repeated almoft all the ex- 

 periments with it which have yet been made public, befides 



making 



