Du 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
bisulphide of carbon. In France, however, a great deal was done. Four
large vessels were fitted with the ether engines, and I went over to
Marseilles to see them at work. I took diagrams from these engines,
and there is no doubt 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
about 22 inches), gave an ether pressure of 15 lb. on the square inch
above atmosphere, and very economical results as regards fuel were
obtained. The scheme was, however, abandoned from practical
difficulties. It need hardly be said that ether vapor is very
difficult to deal with, and although ether is light, the vapor is
extremely heavy, and if there is any leakage, it goes down into the
bilges by gravitation, and being mixed with air, unless due care is
taken to prevent access to the flues, 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
lighting, for instance, was by lamps external to the engine room, and
shining through thick plate-glass. 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.


THE QUICKSILVER ENGINE.

These was another kind of marine engine that I think should not be
passed over without notice; I allude to Howard's quicksilver engine.