35'2 IHJLOSOPHICAL TRANSACTIONS. [aNNO 17/8. 



the same; number of turns ot the wheel with the same velocity, and waiting 

 above 8 seconds also, the same person suddenly caused an explosion with the 

 same hand. But the sensation in consequence of it was very different from the 

 last experiment; for he declared it was little more than half as violent. 



Exp. aQ. I now charged the long wire only and fully, and with one machine: 

 the explosion, in this case, appeared not very large, but of a reddish hue; and 

 the distance it struck at was not more than one inch and a half; however the 

 sensation across the body was at that instant sharp and violent, but not quite so 

 disagreeable as when the great cylinder was connected with it, and similarly 

 charged. 



Exp. 47. Having procured an equal quantity of the same kind of wire, and 

 of the same diameter, with that which was suspended and tried in the last 

 experiment, it was placed in the form of coils on a board, fixed on the top of a 

 long stand of glass, without having any connection with the great apparatus. 

 These coils were then fully charged by the power of one of those machines only. 

 The sensation they afforded, in consequence of causing sparks, was very 

 inconsiderable, compared with what had been observed in the last experiment. 



Exp. 48. The several coils of wire employed in the last experiment, and 700 

 yards more in coils also, were joined together at their several ends. These coils 

 being then strung on silk lines, were drawn out into a form resembling that of 

 a screw, and separated from each other in such a manner all along as to occupy 

 100 yards of silk line. The several diameters of these coils, at a mean, were 

 about 13 inches. As I had so short a time in which to prepare and suspend 

 them properly, the disadvantage of their touching and intersecting each other in 

 many places could not be prevented ; however I found that the sensation caused, 

 after charging this wire, was nearly equal to tliat which had been experienced 

 from the long wire in the 46th experiment. 



Exp. 49. On joining the farther end of these coils to one end of the long 

 wire, so that the whole length was in this experiment about SQOO yards, and 

 afterwards charging the nearer end of the coils, and without the great cylinder, 

 the sensation complained of by two indift'erent persons, was twice as violent 

 as the sensation perceived by the same persons when the long wire alone was 

 charged. 



It may be now proper to make some general observations respecting the 

 explosion itself, and the quantity of the fluid discharged in consequence of it. 

 After many experiments we found, that when the great apparatus was fully 

 charged, and the motion of the wheel suddenly stopped, it appeared, that -a 

 single explosion at either end of it, instantly discharged the contained fluid; but 

 never so effectually as to leave no remainder: for the quantity which did remain 

 was generally sufficient to cause a '2d explosion perceptible to the sense of feel- 



