SIX WILLIAM SIEMENS, F.R.S. 79 



Comparing these theoretical results with the experiments given 

 in Table V., it appeared that in practice with steam of 51 Ihs., 

 or about 3 atmospheres effective pressure, the rise of temperature 

 was 74, while the calculation gave only a little more than 50 ; 

 but then it was assumed that there had been no loss of power by 

 friction, and .the quantity of feed-water propelled into the boiler 

 had been supposed to be the maximum amount theoretically 

 possible. The calculation accordingly gave the minimum rise of 

 temperature when the steam was only just able to balance the 

 pressure of the water tending to escape from the boiler ; and 

 consequently in practice the actual rise of temperature must 

 always be greater than that obtained by the calculation ; but the 

 two results differed not more, he thought, than might be expected, 

 if all losses of effect were taken into account. The table agreed 

 moreover with the calculation in giving a greater rise of tempera- 

 ture at higher pressures of steam ; although the losses of effect 

 must necessarily increase with the pressure, or rather with the 

 increase of velocity of the jet. Much must also depend upon the 

 proper adjustment of the instrument to make the quantity of 

 water injected a maximum. 



In the discussion of the Paper 



"ON AN APPLICATION OF GIFFARD'S INJECTOR 

 AS AN ELEVATOR FOR THE DRAINAGE OF 

 COLLIERY WORKINGS," by Mr. C. W. WARDLE, 



MR. C. W. SIEMENS * said, that although the injector was very 

 beautiful and economical in action where water had to be 

 raised and also to be heated, as in feeding a boiler, it was remark- 

 ably deficient in respect of economy when employed simply as an 

 elevator for raising water, where the water was not required to be 



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

 1861, p. 227. 



