Ward’s Steam-Engine. 95 
dispensable parts of the Steam Engine, in such a way as to 
get rid of all the abovementioned disadvantages. 
In this Engine, the piston-rod is also the connecting-rod.* 
When applied to water-wheels, in propelling boats, the cyl- 
inder is placed within the water-wheel. Two centre-pieces, 
firmly fixed to the boat, one on each side of the recess in 
which the wheel is placed, serve as axes to the wheel, the 
boxes of which turn on necks prepared to receive them ; 
the centre-pieces, after traversing the boxes, are turned at 
right angles and extend, within the wheel and towards its 
circumference, a distance equal to half the sweep of the 
piston ; at this distance from the centre of the water wheel, 
boxes are inserted in the centre-pieces to receive the gudg- 
eons of the cylinder ; the cylinder revolves on those gudg- 
eons about its centre of gravity. ‘The steam is conducted to 
and from the cylinder, by means of a double pipe; so that 
the centre-piece answers the quadruple purpose of an in- 
duction-tube, an eduction-tube, a bearmg for the water- 
wheel, anda bearing for the cylinder. 
The steam is alternately let into each end of the cylinder, 
by a contrivance similar to what was first used, I believe, in | 
ihe Double Cylinder Steam-Engine of Mr. Hornblower ; 
and which will be easily comprehended from the following 
description, taken from Rees’ Cyclopedia: “'The cocks 
of this (Hornblower’s) Engine are composed of two circu- 
lar plates, ground very true to each other, and one of them 
turns round on a pin through their centres: each is pierced 
with three sectorial apertures, exactly corresponding with 
each other, and occupying a little less than one half of their 
surfaces. By turning the moveable plate so that the aper- 
tures coincide, a large passage is opened for the steam; 
and by turning it, so that the solid part of the one covers 
the aperture of the other, the cock is shut.”+ Instead of 
three sectorial apertures, which Hornblower’s Double Cyl- 
inder required, the cocks of my Engine have but two, 
which take up the same space, by being nearly ninety de- 
grees in length each. ‘These cocks are placed by the side 
of my cylinder, the gudgeon of which answers to the “ pin” 
* T have thought the description would be more readily understood, if 
the alphabetical references were kept separate from the text. See the 
figure and its references. 
+ Rees’ Cyc. Art. SrmAM-HNGINE. 
