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13th June 1918, Page 17
13th June 1918
Page 17
Page 17, 13th June 1918 — SHOCKS FROM STEAM VEHICLES.
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THEHIGHLY-INTERESTING scientific phenomenon of the electric charging of metal work is frequently ex4perienced by those who handle steam vehicles. The discovery that escaping steam could generate frictional electricity was made quite accidentally by a workman in charge of a steam boiler and engine near Newcastle some 50 or 60 years ago. Lord Armstrong, the founder of the great armaments firm, was at that time greatly interested in electrical work, and hearing of the discovery he investigated it, and, as a result, invented the. steam or hydro-electric machine which bears his name. One of these he had constructed for the old London Polytechnic, which, in the 'seventies, was a great centre of popular science, the lectures by the well-known Professor Pepper, of now almost forgotten " ghost" fame, being a great feature of those early days.

The Armstrong electric machine for some years drew large crowds to the lectures to see the wonders of electricity, though these would now be considered rather tame, judged by the standards of to-day.. The theory of the generation of. frictional electricity by steam: is rather technical, but it may be said that the particles of water tinter high pressure coming into frictional contact with metal, such as when escaping through a safety valve, produce the same kind of electricity as when a vulcanite penholder is rubbed on one's coat sleeve, and the fact that a steam vehicle is insulated from the earth by its rubber-shed wheels prevents the escape or neutralization of the static electricity generated. The vehicle thus becomes in a 'charged state, and anyone, in contact with the earth, touching any part of the vehicle is liable to receive a smart shock, though by no means a dangerous one, as the actual quantity of electricity in the charge is extremely small. The charging of a steam vehicle can easily be prevented or greatly' minimized by making a permanent earth contact as by means of a trailing chain. It

might be suggested that this electrification of a steam vehicle eould be turned to useful account, but 8tatie or frictional eleeteicity has really no practical value in a commercial sense. .

It is recorded that the old Polytechnic hydro-elec, tric machine produced a continuous stream of sparks ft. in length, and all the effects of lightning on a small scale could be demonstrated with it The boiler was insulated on glass legs which acted similarly to the tyres of a steam vehicle. Very much the same effect in the shape of powerful electrification is often produced by a fast-running link belt, owing to the friction generated by its contact with the steel pulley. An interesting fact is that only "wet" steam can produce frictional electricity, which is proof of the theory that it is the particles of water that play the thief part. A slight amount of metallic impurity in the water is sufficient to prevent the electrification. The generation depends to a considerable extent on the weather, and is at its best in a dry and frosty atmosphere, which improves the.

The pressure of steam has to be comparatively high, about 80 lb. being used in the Arrnstreng machine.


People: Armstrong, Pepper
Locations: Newcastle

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