EXPERIMENTS ON THE ELECTRIC PILE. \1 5 



one of his fingers, and withdrew his finger the moment he 

 brought the large wire into contact with the conductor. This 

 manoeuvre he praetifed repeatedly, till he had acquired a 

 habit of doing it with precision, before he began his com- 

 parative experiments ; fo that he was well allured, that the 

 contact of the conductor, by means of the wire, took no more 

 of the fluid than was furniihed by the machine at the initant 

 of contact. A fingle contacl would not give the battery a The pile of igo 

 change, that tlic electrometer was capable of indicating ; out J^^ the cower 

 by repeated experiments it was found, that fix of thele con- of the machine 



tads of the conductor imparted to the battery the fame in- wit ^ a ? h ]* 3 * 

 r ' inches in diair.e 



tenuty as one contact of the pile. The power ot the machine tCFf 



being equal to about half what the great machine pollened in 

 its former Hate, from 1785 to 1789; but the great machine 

 having gained oonliderably, particularly for charging bat- 

 teries, by the rubbers of the new conftruction applied in 

 1790, and by the uie of Kienmayer's amalgama, fo that its 

 power was rendered the quintuple of what it was before ; 

 the power of the pile of 200 pairs is to that which the great and three- fifths 

 Teylerian machine pouefles at prefent as 3 to 5. The ratio PJ that tne 8 reat 

 could not be examined directly, becaufe a fire cannot be chine.' 

 made in tbe mufeum, and the ground on which it ftands is 

 very damp in winter : this, therefore, is deferred till fpring. 



The fliocks given by the battery,, charged to different de- The fliocks 

 grees of intenfity by contacts with the conductor of the elec- £ iven b y the bat - 

 tric machine, were now compared with thofe it gave with t hl machine, * 

 fimilar inteniities obtained from the pile ; and reiterated trials not at all differ- 

 convinced the experimentalifts, that there was no perceptible gave when ° C * 

 difference between the fenfations or fliocks in the two in- charged by the 

 fiances, provided the inteniities were the fame. Hence Dr. {^j!^.' 1 * 6 ^"^ 

 Van Mar urn concludes, as the effects of fuch a confiderable 

 battery, when charged by the galvanic pile, are precifely 

 limilar, in every refpeft, to its effects when charged by a the two fluids 

 powerful electrical ma- hine, the identity of the fluid put in th eiefore^- 

 motion by the pile with that moved by the electrical madiine'faroe. ° 

 is proved fo decifively, that no one will queftion them in 

 future. Thefe experiments, he adds, joined with thofe of 

 Profeffor Volta, render extremely difputable, or rather com- 

 pletely refute the exigence of a peculiar fluid, in all the other 

 experiments termed galvanic. 



Thefe 



