50 THE SCIENTIFIC PAPERS OF 



heat to form his elastic medium. But it must be borne in mind, 

 that Ericsson had to add to his air a larger amount of sensible 

 heat, of which only a small proportion was really expended in 

 expansion, and the remainder would go to waste, unless it was 

 recovered by the regenerator. Nevertheless, the drawbacks to 

 Ericsson's engine, on account of the great resistance of the pump, 

 the small working pressure, the insufficiency of heating surface, 

 and the working of a piston in a heated cylinder, were so great, 

 that he thought no beneficial results could be expected from it. 



ON A REGENERATIVE STEAM-ENGINE. 

 BY C. W. SIEMENS, Esq., C.E.* 



THE application of the steam-engine to our various purposes of 

 manufacture and locomotion is of very recent date, although the 

 elastic force of steam was known even by the ancients ; for we read 

 in Hero of Alexandria, on Pneumatics (translation by Woodcroft) 

 that the Egyptian priesthood made use of it for the somewhat 

 undignified purpose of performing pretended miracles before an 

 ignorant population. The first suggestion of its useful application 

 for raising water is due to the Marquis of Worcester, and dwelt 

 upon in his " Century of Inventions." 



The idea was taken up by Papin, Savory, and Newcomen, who 

 added important elements towards its practical realization ; but to 

 James Watt belongs the merit of having laid down a comprehensive 

 principle of the steam-engine, and of having devised means to 

 render the same capable of performing the rudest as well as the 

 most delicate operations. 



If any proof were wanting of the great genius of Watt, it would 

 be sufficient to observe that the steam-engine of the present day is, 

 in point of principle, still the same as it left his hands half a cen- 

 tury ago, and that our age of material progress could only affect 



* Excerpt Minutes of Proceedings of the Royal Institution of Great Britain 

 Vol. II. 1856, pp. 227-236. 



