Mr. W. G. Armstrong on the Electricity of Effluent Steam. 4-55 



and upon which cock is screwed a second glass tube D ter- 

 minating in another stop-cock E. 



The application of this apparatus will be 

 easily understood. If the steam were in the 

 same state of electricity in the boiler as when 

 it issued into the air, it would necessarily com- 

 municate positive electricity to the insulated 

 cock C, in passing through the tube. Or, if the 

 steam acquired its electricity by friction, or 

 otherwise, in the channel through which it was 

 discharged, it could only, in the present instance, 

 do so at the expense of the cock C, which, being 

 insulated, would in that case indicate negative 

 electricity. Or, lastly, if the electricity were 

 developed by condensation, expansion, or any 

 other cause which came into operation after the 

 steam escaped into the air, then the cock C 

 would have neither positive nor negative elec- 

 tricity. 



Previously to inserting the lower glass tube in 

 the boiler, the steam was allowed to blow off 

 through the large cock B, and the jet which issued 

 from it proved, to the surprise of every one pre- 

 sent, almost destitute of electricity. This result 

 completely vitiated the inference I had drawn 

 from the circumstance of not finding electri- 

 city in the steam from the rain-water boiler 

 before alluded to, in which case, as I have al- 

 ready stated in my second letter to Professor 

 Faraday, the jet was obtained from the gauge 

 cock. 



The lower glass tube, without the upper one attached to it, 

 was then passed into the boiler, and a highly electrical jet 

 was obtained from it, which communicated positive electricity 

 to the stop-cock C, from which the steam was discharged. 

 The upper tube was accidental ly broken in screwing it on to 

 the lower one, leaving only about three inches of glass above 

 the cock C. Under these circumstances the cock C still con- 

 tinued highly charged with positive electricity, and a pale 

 lambent light flashed at short intervals down the inside of the 

 tube from the cock towards the boiler. 



Having replaced the broken glass tube with a new one, the 

 experiment was tried again on a subsequent evening, and 

 the jet being now removed to a much greater distance than 

 before from the cock C, no electricity whatever could be de- 

 tected in that cock, while the one above it indicated positive 



