500 itEroRT — 1881. ■ 



and he gave some account of that which was done by M. Du Tremblay 

 in this direction. It so happened I had occasion to investigate the 

 matter at the time of Da Tremblay's experiments. Very little was 

 effected here in England, one difficulty being the excise interference 

 with the manufacture of ether. Chloroform was used here, and it was 

 also suggested to employ bi-sulphide of carbon. In France, however, a 

 great deal was done. Four large vessels were fitted with the ether- 

 engine, and I went over to Marseilles to see them at work. I took 

 diagrams from them, and found that by this system the exhaust steam 

 from the steam-cylinder, which was condensed by the application of 

 ether to the surface of the steam-condenser (producing a respectable 

 vacuum of 22 inches), gave an ether-pressure of some ISlbs. on the 

 square inch ahove atmosphere, and that very economical results as 

 regards fuel were obtained. The system was, however, eventually aban- 

 doned, owing to pi'actical difficulties. It need hardly be said that ether- 

 vapour is very difficult to deal with, and although ether is light the 

 vapour is extremely heavy, and if there is any leak in the appai-atus the 

 vapour goes down into the bilges by gravitation, and being mixed with 

 air, unless due care is taken to prevent access to the fires, there would 

 be a constant risk of a violent explosion. In fact, it was necessary to 

 treat the engine-room in the way in which a fiery colliery would be 

 treated ; the light, for instance, was by lamps external to the engine-room, 

 and shining through thick plate glass, while the hand-lamps were 

 Davy's. The Ether Engine was a bold experiment in applied science, and 

 one that entitles Du Tremblay's name to be preserved and to be mentioned 

 as it was by our President. There was another kind of marine engine 

 that I think should not be passed over without notice. I allude to 

 Howard's Quicksilver Engine. The experiments with this engine were 

 persevered in for some considerable time, and it was actually used for 

 practical purposes in propelling a passenger vessel called the Vesta, 

 running from London to Ramsgate. In that engine the boiler had 

 a double bottom containing an amalgam of quicksilver and lead. This 

 amalgam served as a reservoir of heat, which it took up from the fire 

 below the double bottom, and gave forth at intervals to the water 

 above it. There was no water in the boiler, in the ordinary sense of 

 the term, but when steam was wanted to start the engine, a small 

 quantity of water was injected by means of a hand pump, and after the 

 engine was started there was pumped by it into the boiler, at each half- 

 revolution, as much water as would produce the steam needed. This 

 water was dispersed on the top surface of the reservoir in which the 

 iimalgam was confined, and was entirely flashed into steam, the object of 

 the engineer in charge being to send in only so much as would just 

 •generate the steam, without leaving any water in the boiler. The 

 -engines of the Vesta were made by Mr. Penn for Mr. Howard, of the 

 King and Queen Ironworks, Rotherhithe. Mr. Howard was, I fear, a 

 considerable loser by his meritorious efforts to improve the steam-engine. 



The President : What sort of results did they get in point of economy ? 



Sir Frederich Bramwell : I don't know, but I believe they got 

 moderately good results. There was used with this engine an almost un- 

 known mode of obtaining fresh water for the boiler. Fresh water, it will 

 be seen, was a necessity in this mode of evaporation, as the presence of 

 salt or anj"- other impurity when the whole of the water was flashed into 

 steam, must have caused a deposit at the top of the amalgam chamber 



