54 Mr. W. G. Armstrong 07i the Electricity of Effluent Steam. 



had previously done while the boiler communicated with the 

 earth by means of the iron bar. 



It is important to state that when the balls were repelled 

 with negative electricity, they collapsed very considerably when 

 the cock was touched by the hand, but when they diverged 

 with i^ositive electricity no effect was produced by touching 

 the cock, which strongly favours the supposition that the 

 positive electricity manifested by the lower pith-balls, was 

 conducted to the cylinder from the jet. 



A coil of lead pipe, immersed in a glas jar filled with wet 

 snow, was then placed upon the insulating stool and connected 

 with the tube B, after the brass cylinder had been detached ; 

 and the iron bar was again placed against the boiler to suspend 

 the insulation. Upon opening the cock to the full extent, 

 little or no electricity could be discovered in the coil, but 

 when the cock was partly closed, positive electricity appeared 

 for a short time and then faded away exactly as in the expe- 

 riments with the brass cylinder. Upon removing the con- 

 nexion between the boiler and the earth and raising the valve 

 the coil became highly negative, but upon closing the valve 

 the negative electricity vanished. 



I have little doubt that the predominance of the negative 

 over the positive electricity in the above experiment is attri- 

 butable to the conducting power of the steam causing more 

 negative electricity to be conveyed to the coil from the boiler, 

 than the coil would acquire if the steam were a non-conductor. 

 When negative electricity was in like manner so strongly 

 manifested by the pith-balls in the experiments with the brass 

 cylinder, it was noticed, that after closing the cock, while the 

 interior of the tubes were bedewed with moisture, scarcely 

 any negative electricity was transmitted to the balls, so that 

 the conducting power must have been in the steam, and not 

 in the mere dampness on the glass. 



A vertical glass tube, about an inch in diameter, and be- 

 tween two and three feet long, was then screwed on to the 

 cock in substitution of the tube B. The lower part of this 

 tube contained a number of pointed wires for the purpose of 

 abstracting and imparting to the cock any electricity which 

 the steam might possess on entering the tube. When the 

 cock was now fully opened, flashes of light began to dart 

 through the whole length of the tube, from the cloud above 

 it to the cock, and continued to do so as long as the cock re- 

 mained open, both when the boiler was insulated, and when 

 it was connected with the earth. The steam in the tube was 

 perfectly transparent, and no moisture could be seen on the 

 inner surface of the glass. 



