Electro-Magnetic Engine. (From the Artizan )

Daily Southern Cross, Volume I, Issue 34, 9 December 1843, Page 4

Electro-Magnetic Engine. (From th e Artizan )

This is an engine now exhibiting at the Egyptian Hall for obtaining a motive power from galvanism through the agency of a tern ■ porary magnet. The principle of the plan is thrown into a variety of different shapes, of which the most interesting in our eyes, is that by which a rotary motion is imparted to a drum of wood and iron dispose in alternate radial layers. We must endeavour to make the modus operandi of this machine intelligible to those of our readers who may not have had an opportunity of visiting the exhibition. In the drum, which is for the most part composed of wood, three large pieces of iron are inserted ; and on the frame which supports the drum two large horse-shoe pieces of iron, wrapped round with copper wire, are

fixed — one before the drum, and the other behind it. By a proper arrangement of little cans on the shaft of the drum, the copper wire wound round each of the pieces of iron is connected ond disconnected with a galvanic battery, alternately ; and when the battery is connected with the one piece of iron, it is [ disconnected with the other ; so that when one of the pieces of iron is changed into a temporary magnet by the galvanic current, the other remains only a piece of inert iron. { The consequence of this arrangement is, that j the horse-shoe piece of iron, which is pro j tempore changed into a magnet, attracts the j peace of iron nearest to on the drum, thus putting the drum into revolution ; and by the time that the revolution of the drum has brought this piece of iron opposite to the magnet, the cans have changed the connection of the wires, so that the piece of iron which has just been acting as a magnet becomes inert, and the piece of iron on the other side acquires magnetic efficacy, by which means the rotation of the drum is continued. The value ef all such means of acquiring motive power depends altogether upon its economy in comparison with other methods. Mr. Davidson, by whom these machines have been invented, informs us that the power he consumes is actually produced at no cost ; inasmuch as the sulphate of zinc produced by the action of the acid upon the plates in the galvanic trough will realise by its sale more than sufficient to replace the plates and acid. But we do not think this would be the case if the plan were to come into any considerable use, as the sulphate of zinc, being an article of limited consumption, would not meet with an increased sale corresponding to the increased production, and would therefore fall in price. Nevertheless the salts of zinc are fast coming into a more extended use ; they are, for example now used in preserving timber from rotting, and in coating iron with metallic zinc, and the demand for them would no doubt be much increased if their mode of production could be considerably cheapened. "Still, we fear, with these additional outlets, the salts of zinc would, if Mr. Davidsons plan were to be adopted to any considerable extent, become # drug in the market ; and we do not, therefore, anticipate that his plan -will ever supersede the steamengine, so long as it clogged by the objection to which we have averted. Cheaper means, however, may be found out of generating the galvanic fluid, and when that is done, some such machine as Mr. Davidsons must supersede the existing methods of producing motive power- _»_ MM — ___.-_—.