454 Mr. W. G. Armstrong on the Electricity of 'Effluent Steam. 



the abstraction of electricity from the steam, and a sprin- 

 kling of wet was undoubtedly felt on the face and hands 

 by the person holding the rod, so long as he remained in- 

 sulated, but the effect ceased as soon as the insulation was 

 destroyed. 



After fully trying the steam with a simple iron rod, as a 

 conductor, recourse was had to other conductors which pre- 

 sented a larger surface to the steam, but the effect was not 

 materially increased until a bunch of pointed wires of different 

 lengths was attached to an iron rod and held in the issuing 

 steam, with the points presented downwards. The iron rod 

 terminated in a round knob at the end next the hand, and 

 from this knob sparks of the measured length of four inches 

 were actually drawn, almost as rapidly as they could be 

 counted, while a stream of electricity was at the same time 

 passing off from the rod, at the part which most nearly ap- 

 proached the chimney of the engine. Very perceptible sparks 

 were also obtained when the points were held in a clear at- 

 mosphere, at the distance of at least eight feet from the nearest 

 part of the jet. 



In all the preceding experiments, the effect appeared to be 

 proportionate to the quantity of steam discharged from the 

 valve, when other things remained the same ; and the elec- 

 tricity became quite imperceptible when the escape was very 

 inconsiderable. 



By abruptly raising the valve when the engine-shed was 

 dark, the edges of the lever and margin of the brass cup 

 which surrounded the valve, were rendered distinctly lumi- 

 nous with rays of positive electricity which were strongest 

 the instant the valve was lifted, and then quickly subsided, 

 becoming very faint after the lapse of a second. 



In proceeding to investigate the cause of this extraordinary 

 development of electricity, the first question which 1 proposed 

 for inquiry was, Where does the steam first become electri- 

 cal, that is to say, is it electrical in the boiler, or if not, does 

 it become so in passing through the orifice, or not till it 

 escapes into the air? In order to determine which of these 

 three suppositions was correct, the apparatus represented 

 in the annexed figure, and of which the following is a de- 

 scription, was employed. 



A is a glass tube passing into the steam chamber through 

 the cock B, which was screwed into a hole in the top of the 

 boiler, and was furnished with a stuffing-box to prevent escape 

 between the outside of the tube and inner surface of the cock; 

 C is a stop-cock affixed to the upper end of the glass tube, 



