72 THE SCIENTIFIC PAPERS OF 



amount of condensed steam. In the absence of direct experi- 

 ments on that point, he thought it might be assumed, that a given 

 volume of steam would produce an equal volume of ether vapour 

 of the same pressure. That would appear to be the result of 

 general theory. The practical question was, how far the extra 

 power obtained by the ether-engine might be realised, by working 

 steam to a very high degree of expansion. The unprotected 

 cylinder of a marine engine would not give a favourable result, 

 because the steam generated in the boiler could not be dealt with 

 as a permanently elastic fluid, as had been too much the practice, 

 but would lose much of its elastic force through condensation in 

 the cylinder. The old engines of Watt were not simply lined 

 with a conducting material, as was now thought sufficient by many 

 Engineers, but were supplied with a steam-jacket kept filled with 

 steam of higher tension than the working pressure, to make up for 

 the loss of heat sustained in expansion. By properly protecting 

 the cylinder, by means of a complete steam-jacket, against the 

 enormous loss sustained by condensation of the high-pressure 

 steam upon the sides of the cylinder, and re-evaporation from 

 the same surfaces, after expansion had taken place, he thought 

 results might be obtained, equal to those claimed for the ether- 

 engine. There was no doubt, however, that the combined ether- 

 engine might, in its turn, be still greatly improved, if the practical 

 disadvantages of the greater complication, and of the danger 

 arising from the leakage of the ether vapour, should not prevent 

 its extended application. 



In ihe discussion of the Paper 



"ON THE APPLICATION" OF SUPERHEATED 

 STEAM," by Mr. JOHN N. RYDER, 



MR. C. W. SIEMENS* said he had seen the trial of superheated 

 steam that had been referred to at Messrs. Hoyle's works ; and 



* Excerpt Minutes of Proceedings of the Institution of Mechanical Engineers, 

 1860, pp. 30-33. 



