54 Ruthven's Hydraulic Propeller. 
another small vessel, thirty feet long, built, to illustrate his 
invention. This was placed on the Thames, and a smaller 
one, of twelve feet, sent to the Great Exhibition of 1851. 
The one on the Thames attracted a great deal of notice, and 
was spoken most favourably of, one steamboat company 
proposing.to take up the invention, but ultimately aban- 
doning the idea, stating as a reason that it would, if suc- 
cessful, throw out of use the many boats they had already 
on the river. 
The Exhibition model fared worse (though it was in 
reality one of the most valuable inventions to commerce in 
the World’s Fair) it not being so much as even noticed in 
the Juror’s Report. | 
As in the case of the needle-gun, so with this, the Prus- 
sian Government undertook part of the expense of building 
a boat, which was done by a Mr. Sydel, the engines and 
other machinery being furnished by Mr. Ruthven. The 
building of this vessel, which was in 1853, proved the 
acumen of the Prussian Government, it having been run- 
ning regularly ever since on the Oder, and has proved the 
complete success of this invention. 
Having thus entered into the history of the up-hill work 
which the inventor has had in urging this mode of propul- 
sion upon practical men, we now come to the descriptive 
portion of our task, and in order to render these remarks 
as plain as possible, we shall here introduce two engravings, 
one a transverse section, and the other a plan of engine and 
propeller -— 
Fic. 1.—Transverse Section—showing arrangements on deck for 
turning valves. 
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