Heroes of the Telegraph

Various papers read before the Institution of Mechanical Engineers, the Institution of Civil Engineers, or appearing in DINGLER'S JOURNAL and the JOURNAL OF THE FRANKLIN INSTITUTE about this time, illustrate the workings of his mind upon the subject. That read in 1853, before the Institution of Civil Engineers, 'On the Conversion of Heat into Mechanical Effect,' was the first of a long series of communications to that learned body, and gained for its author the Telford premium and medal. In it he contended that a perfect engine would be one in which all the heat applied to the steam was used up in its expansion behind a working piston, leaving none to be sent into a condenser or the atmosphere, and that the best results in any actual engine would be attained by carrying expansion to the furthest possible limit, or, in practice, by the application of a regenerator. Anxious to realise his theories further, he constructed a twenty horse-power engine on the regenerative plan, and exhibited it at the Paris Universal Exhibition of 1855; but, not realising his expectations, he substituted for it another of seven-horse power, made by M. Farcot, of Paris, which was found to work with considerable economy. The use of superheated steam, however, still proved a drawback, and the Siemens engine has not been extensively used. On the other hand, the Siemens water-meter, which he introduced in 1851, has been very widely used, not only in this country, but abroad. It acts equally well under all variations of pressure, and with a constant or an intermittent supply.