SIR WILLIAM SIEMENS, F.R.S. 15 



described may be advantageously applied to marine engines ; and 

 not being subject to a patent, he hopes it will receive a sufficient 

 trial. 



I'.cing required to save the waste steam of a low-pressure engine 

 in the form of slightly heated water, for Mr. John Graham of 

 Manchester, the author in the spring of 1847 conceived the idea 

 of a regenerative condenser. Figs. 4 and 5, Plate 2, show his 

 first arrangement as already described, which may be termed a 

 regenerative surface condenser. It consists of a revolving valve 

 B, which admits the waste steam of the engine first to the atmos- 

 phere at C, and then successively into the separate compartments, 

 D, E, F, G, where it is condensed at various densities. The cold 

 water enters at H, and first passes between the plates within the 

 last compartment G, and by degrees through those within the first 

 compartment D, where the steam is of nearly atmospheric pressure, 

 and consequently heats the water to nearly 212 Fahr., when it 

 passes out at I. 



The next step was a regenerative injection condenser on the 

 same principle, as represented by Fig. 6, Plate 2. The revolving 

 valve B admits the waste steam of the engine first to the atmos- 

 phere at C, and then successively into the separate compartments, 

 D, E, F, G, where it is condensed at various densities. The cold 

 water is injected at H, and is passed down through the steam in 

 each compartment in succession by means of the displacing 

 pistons K K, which work all on the same piston rod through each 

 of the divisions between the compartments ; and the heated water 

 passes out at the bottom at I. L L are overflowing distributing 

 trays, for the purpose of bringing the water more rapidly and 

 completely into contact with the steam. M is a small pump to 

 extract the air that is mixed with the steam and water. 



The regenerative condenser in its present form partakes of the 

 nature of both the surface and the injection condensers. 



Attempts have been made from time to time to condense the 

 steam of a high-pressure engine without the aid of an air pump, by 

 blowing the steam into a small injection condenser which is 

 provided with a large exhaust valve. It is clear that the steam of 

 high pressure will at first partially blow through the condenser, and 

 rid it of its air and condensing water ; and that by degrees the jet 

 of cold water will overpower the influx of steam, and consequently 



