VOL. LI.] PHILOSOPHICAL TRANSACTIONS. 41/ 



the two powers to make different holes in the paper ; but that they always keep 

 the same common channel, rushing along it with inconceivable impetuosity, 

 and in contrary directions. They seem to pass each other much about the middle 

 of the quire ; for there the edges are most visibly bent different ways : whereas 

 in the leaves near the outside of the quire, the holes very often carry more the 

 appearance of the passage of a power issuing out, and exploding into the air, 

 than of one darting into the paper. 



2". — When any thin metallic substance, such as gilt-leaf, or tin-foil, is put 

 between the leaves of the quire, and the whole is struck ; in that case the coun- 

 teracting powers deviate from the direct track, and leaving the path they would 

 in common have taken through the paper only, make their way in different lines 

 to the metallic body, and strike it in two different points, distant from each other 

 about a quarter of ah inch, more or less (the distance appearing to be least when, 

 the power is greatest) ; and whether they pierce, or only make impressions on it, 

 in either case they leave evident marks of motion from two different parts, and 

 in two contrary directions. It is this deviation from a common course, and the 

 separation of the lines of direction consequent on it, that affords us the strongest 

 proof of the exertion of two distinct and counteracting powers. 



3". — When two slips of tin-foil are put into the middle o( the quire, including 

 two or more leaves between them, if the electricity be moderately strong, the 

 counteracting powers only strike against the slips, and leave their impressions 

 there. When it is stronger, we generally find one of the slips pierced, but 

 seldom both ; and from what is observed in such cases, it would seem as if the 

 power which issued from the outside of the phial, acts more strongly than that 

 which proceeds from within, for the lower slip is most commonly pierced; but 

 that may be owing to the greater space the power from within has to move 

 through, before it strikes the paper. 



Paper iv. part ii. — Of two Distinct Powers in Electricity. 



The notion of two distinct electrical powers, acting in contrary directions, 

 may appear to some to be the same with that of the effluence and affluence of 

 electrical matter, which M. I'Abbe Nollet gives as the general cause of the phe- 

 nomena of electricity. It may therefore be not improper to take a nearer view 

 of these two opinions, to see how far they agree, and in what they differ. 



This ingenious author had observed that when a body is electrified, a current 

 of electric fluid issues from it, and in the form of diverging rays spreads through 

 the air, and enters into other bodies; and that, at the same time, a current of 

 electric fluid, issuing from other bodies, passes through the air, and in the form 

 of converging rays enters into the body electrified. Hence he concludes, that 

 a continued, and (to use his own terms) simultaneous effluence and affluence of 



VOL. XI. 3, H 



