SfX WILLIAM SIEMENS, F.R.S. 9 



in operation in consequence of a deficiency of injection water. 

 The actual indicator diagram, shown in Fig. 3, Plate 2, was 

 taken from this engine ; since then several more of the regenera- 

 tive condensers have been erected, and the results above referred 

 to have been obtained. The dotted line in Fig. 8 shows the 

 indicator diagram taken from the engine before the condenser was 

 applied ; and the full line shows the diagram from the engine 

 working with the condenser, and exerting exactly the same power 

 as in the former case. The shaded portion of the diagram shows 

 the power gained or saved by the use of the condenser. 



The advantages attending the application of the regenerative 

 condenser to stationary engines being practically proved, the author 

 is desirous to extend it also to that important class the locomotive 

 engine. In inviting the attention of railway engineers to this 

 enquiry, he is prepared for practical objections being raised on 

 account of the great rapidity of motion, the necessity for the 

 greatest possible simplicity and lightness, the deficiency of con- 

 densing water, &c. ; but he thinks that the condenser under 

 consideration is peculiarly well adapted to meet these objections. 



The peculiarities of the regenerative condenser in this respect 

 are as follow. ' It may be accommodated to any speed of piston, 

 by reducing the length and increasing the breadth of the condens- 

 ing plates, thus reducing the velocity of the displacing piston 

 proportionately. Its dimensions are proportionate to the capacity 

 of cylinder only, and not, as in other condensers, to the horse- 

 power of the engine. The total weight of a pair of condensers, 

 as applied to a locomotive engine with cylinders of 13 inches 

 diameter and 20 inches stroke, is about 3 cwts. The power of 

 the blast remains nearly undiminished. The condenser requires 

 no attention in working the engine, and in case it should fail to 

 act from any accidental cause the engine will continue to work 

 high pressure as usual. Moreover it does not interfere with the 

 working parts of the engine. 



The advantages which would result from a vacuum in the cylin- 

 der of a locomotive engine have been ably set forth by Mr. Edward 

 "Woods in his " Observations on the consumption of fuel and 

 evaporation of water in locomotive and other steam engines." 

 The present paper may therefore be limited to the means proposed 

 for that purpose. 



