i 3 8 Experiments on the Charges of Bodies 



was different according to the different situations in which it was placed 

 in respect of the vial A, or according to the different shape of the wire 

 sSRr by which it was touched, or according to the different parts in which 

 it was touched by that wire. The body which I used for this purpose was 

 a square tin plate, 12 inches each way, and the different ways in which 

 it was tried are drawn in Fig. 17, which represents a plan of the disposition 

 of the whole apparatus, in which the letters B, d, D, 8, t, m, M, N, a, 

 A, S, R and r represent the same things as in Fig. 14. 



266] 1st Way. The tin plate was placed in a vertical plane so as to 

 be represented in the plan by the line 6/J, the wires Rr and Dd when let 

 down resting on the edge of the plate as in the figure. 



2nd. The tin plate was placed horizontal, as represented by the square 

 Bcfg, the plate being placed so that the wire Rr touched it near the 

 middle. N.B. The wire Rr was bent at right angles about f of an inch 

 from the end r, so that -f of an inch was in a vertical situation, and the 

 rest horizontal. Consequently the wire touched the plate only by its 

 extremity. 



3rd. The same as the last, except that the wire Rr touched the plate 

 not far from the side fg, and pretty near the middle of that side. 



4th. The same as the last, except that a cross wire eE was fastened 

 horizontally across the wire Rr, so as to be parallel to the side fg, and 

 about one inch distance from it. 



5th. The plate in the same situation as before, but the wire Rr was 

 bent into an arch, like tTR, only the plane of that arch was vertical. The 

 wire touched the plate near the middle. 



6th. The plate in the same situation as before, but the wire Rr was 

 removed into the situation yx, the communication between y and 5 being 

 by the wire yzS bent into an arch, as in the figure, the plane of which was 

 vertical. The wire yx touched the plate near the middle. 



N.B. In all these ways the tin plate was supported on silk lines. 



267] The charges of the plate in the different situations were found 

 to be to each other in the following proportions? 1 : 



1st Way. . . . 11-7, 



2nd . . . . 11-7, 



3rd . . 12-0, 



4th . . 10-8, 



5th . . . . 11-5, 



6th . . . . 10-8. 



* [Art. 470, Dec. 17, 1771. The numbers there found are here multiplied by a 

 constant, so as to make the result by the 3rd way equal to 12.] 



