350 Mr Rowell on the Electricity of Steam. 



ing a tendency to resist dampness, would prevent the supply 

 of sufficient electricity to cause any strong development- 



Every insulated substance held in the current of steam from 

 ivory or quill tubes became negatively charged, from the steam 

 taking off a portion of their electricity. 



That electricity cannot be obtained from currents of low 

 pressure steam, may be accounted for by the increased con- 

 ducting power of steam in this state preventing any develop- 

 ment of electricity in the condensed steam, by conducting the 

 electricity back to the boiler the instant any accumulation 

 takes place : even the addition to high pressure steam of any 

 saline or other substances (which increases the conducting 

 power of water) prevented electrical development. 



It is difficult to account for the absence of electricity when 

 the valve of the boiler was lifted, in Dr Faraday's experiments, 

 as both Mr Armstrong and Mr Pattison performed most of 

 their early experiments from the safety valves of several boilers, 

 and Mr Armstrong states that on one occasion " the engine 

 was rendered intensely negative by a copious emission of steam 

 from the valve." It may be owing to the small pressure on the 

 boiler used by Dr. Faraday. 



"With respect to the cause why oil of turpentine, olive oil, 

 &c., renders the steam negative, I can form no opinion, but 

 believe that any substance which would reduce the conduct- 

 ing power from the boiler to the mouth of the tube, in any 

 great degree, would render the stream of steam negative, by 

 preventing the particles of steam obtaining their coating of 

 electricity. 



The increase of electricity, with the increase of pressure 

 on the boiler, may be accounted for ; as the expansion of 

 steam on escaping from the boiler increases also with the 

 pressure. 



