494 Mr. R. Phillijjs on Electricity and Steam. 



56. The piece of a gun -barrel (20.) was now placed with 

 proper precautions before the jet, and by means of wire con- 

 nected with the boiler. The boiler was positive, and the 

 steam powerfully positive even at a distance from the jet of 

 4 leet 3 inches, the current of air at that distance being a 

 mere breeze; and I doubt not that had it not been for the 

 wall, I could easily have obtained plus electricity at double 

 the distance. From this it clearly follows that the plus elec- 

 tricity of the steam cannot be generated by friction against 

 tlie gauze. Neither does friction in the tube generate it, for 

 the effect was obtained without a tube (55.); nor can it be 

 generated by friction in the brass jet, for this frictional elec- 

 tricity was found to leave the boiler negative, which negative 

 electricity was not nearly equivalent to the positive of the 

 steam (55.); to which I may add the similar experiments with 

 the tubes, the tubes being evidently collectors only and not 

 generators of the electricity of the steam. 



57. It would seem as though positive electricity only, with- 

 out negative, was generated in these experiments; however, it 

 is not so. 



58. The single-leaf electrometer was now placed in the vial- 

 holder of a microscope, through which the motions of the gold- 

 leaf were observed by a power of about 200 tliameters, a micro- 

 meter eye-piece being employed. Also a thin piece of metal, 

 2 inches by 6 inches, was fixed on an insulated support, the 

 greater length of the plate being about perpendicular to the 

 horizon. This metal plate was now placed at a little distance 

 from the end of the former gun-barrel arrangement [56.)^ and 

 sufficiently distant from the path of the steam to be out of the 

 way of the straggling drops of water ; this screen was now con- 

 nected with the electrometer, and the boiler carefully connected 

 with the earth. When the steam was turned on, the electro- 

 meter received a negative charge. The extent of the motion of 

 the leaf was very variable, depending, 1 think, on the amount 

 of water discharged with the steam; on the average, I reckoned 

 it about five micrometrical divisions. A brass tube, 6 inches 

 long and ^^ inch diameter, was now janmied on the end of 

 the gun-barrel, to increase its length, and the inducteous 

 plate was placed at the end of it, as before at the end of the 

 gun-barrel. The steam now being turned on, the leaf moved 

 over between twenty and thirty divisions. 



59. it was easy to become convinced that these motions of 

 the leaf were really produced by induction, by turning on the 

 steam and allowing the leaf to obtain its deviation and then 

 quickly shutting off" the steam, when the leaf would promptly 

 fall back. Also with the brass tube on, I managed to charge 

 the instrument positively by turning on the steam, then open- 



