29 JANUARY 1842, Page 13

RAILWAY-TRAIN-ARRESTER.

A FRESH achievement of the infant science of electro-magnetism was made known to a select few at the Polytechnic Institution on Thursday evening. To sound the depths of the sea, to register the march of Time, to communicate thought and print it with lightning speed,— these were known to be faits accomplis by electro-magnetic power : it now puts forth its arm to arrest the apparently resistless momentum of a railway-train. Assuming that the magical wires through which the mys- terious power is transmitted are laid down, nothing more is required to do this than a small voltaic battery placed on the engine, in connexion with an electro-magnet, some clock-work, and a pilot locomotive in ad- vance of the train. It is through this "pilot" that the communications of the wires with the battery are made. When in motion, the con- nexion is broken by the application of Wierr's contrivance of the "go- vernor." Should any obstacle stop the pilot, the arms of the governor fall, and the connexion being then made, the electro-magnet comes into play most effectively. Its first act is to point the hand of a dial to the word "danger." Should the engineer not see this warning, a bell rings to rouse him. Should he be asleep or drunk, the next operation of the apparatus is to put down the breaks ; and lastly, to turn off the steam, and thus stop the train before it reaches the avant-eoureur. These ef- fects would be produced at a distance from the pilot of two miles, though three or four hundred yards is the farthest contemplated as practically useful. To explain the modus operandi so as to be generally comprehen- sible, would require long descriptions and diagrams : it is enough here to state, that the inventor showed, by his explanations and models, that the thing can be done. Whether it will be done, we doubt. The first expense of laying down the wires and the pilot-engine will make rail- way-directors question the practicability of the plan. The invention is, however, a step towards dispensing with the services of engine-drivers by making the locomotives self-acting. If Mr. BAIN, the inventor, in his next researches in the region of science he has explored so success- fully, should discover electro-magnetic engineers, he will find more fa- vour in the eyes of passenger-propelling companies.