1 44 Theoretical conclusions 



and that it is not likely that the last should. This is also confirmed by the 

 near agreement of the results in both ways of trying the experiment, as 

 the difference in the proportion of the charges in these two ways of trying 

 the experiment was not greater than what might well be owing to the 

 error of the experiment. 



278] It seems reasonable to conclude, therefore, that the proportion 

 which the charges ought to bear to each other in the theory on the sup- 

 position of their being connected by canals of incompressible fluid, and 

 of the electrical attraction and repulsion being inversely as the squares 

 of the distances, must be nearly as in the last Table, and therefore it 

 should seem that the observed charges of the two small plates were rather 

 less in proportion to that of the large one than they ought to have been 

 by theory on the above-mentioned supposition ; but the difference is not 

 great, and perhaps not more than what may be owing to our not being 

 able to compute the true proportion with sufficient accuracy, and to the 

 error of the experiment, though I am more inclined to think that the 

 difference is real. This, however, can by no means be looked upon as a 

 sign of any error in the theory, but, on the contrary, I think that the 

 difference being so small is a strong sign that the theory is true. For it 

 cannot be expected that the charges of bodies connected together by wires 

 should bear exactly the same proportion to each other that they should 

 do if they were connected by canals of incompressible fluid; and, indeed, 

 the third experiment shews that they do not, as the charge of the tin 

 plate was found to be a little different according to the situation in which 

 it was placed and the disposition of the wire by which it was touched, 

 which should not be the case if it was connected to the vial by a canal of 

 incompressible fluid. 



279] EXP. VI. This experiment was made with the same view as the 

 last, and consisted in comparing the charge of two brass wires together, 

 with that of a single one of twice the length and thickness. The small 

 wires were 3 feet long and Jffth of an inch thick; they were placed hori- 

 zontal and parallel to each other, as represented by the lines Bb and Cc 

 in Fig. 18, and were tried at three different distances from each other, 

 viz.: 18, 24, and 36 inches. The long wire was 6 feet long and Jth of 

 an inch in thickness, and was placed in the same direction as the small 

 ones, as represented by Ee, They were electrified by the same wires and 

 in the same manner as the circles, only they were placed so as to be touched 

 by the wires//?, rR, and gR, very near their extremities b, c, and c. Their 

 charges were as follows : 



The long wire i-ooo, 



The two short ones at 36 inches distance -903, 



24 -860, 



18 ,, -850. 



