Ward's Steam-Engine. i0] 
as you lessen the time, you increase the velocity, and, of 
course, the momentum. In the lever engine, this transfer 
takes place four times, during every revolution ; that is, the 
beam is accelerated and retarded, during the first half of the 
revolution, and again accelerated and retarded, during the 
other half. In my engine, the transfer takes place but twice 
in the whole revolution ; that is, the cylinder is accelerated 
during one half, and retarded during the other. If, then, we 
suppose the revolution, in each case, to be performed in the 
same time, it follows, that two transfers of momentum occur 
in the lever engine, inthe same time that one only takes place 
in mine ; and that the velocity and momentum and strain, 
at each transfer, are twice as great as in mine. ‘The strain 
is also greater from two other circumstances ; first, because 
the weight of the cylinder, which is the body accelerated 
and retarded in my engine, is not so heavy as the beam; and 
secondly, because it is placed nearer the centre of motion 
than the parts of the beam.—2. As the steam contained in 
the tubes, extending from the cocks to the ends of the cyl- 
inder, is necessarily lost at each revolution, the shorter these 
tubes are, the better; and the cocks being placed, in my 
engine, onthe sides of the cylinder, the aggregate length of 
these tubes is no greater than the length of the cylinder it- 
self.—3. The friction is much diminished, both because 
fewer pieces of machinery are employed, and because the 
action and reaction are sustained by gudgeons, which always 
revolve the same way,—except those of the cross-piece at 
the head of the piston-rod, which have a vibratory motion. 
4. There being less use of steam, of course less fuel will be 
necessary ; and this is not only a saving of expense, but of 
room also, and freight; since it is well known, that the bulk 
and weight of the wood consumed, in the common steam- 
boats, cause a material drawback on the profits of those es- 
tablishments.—5. Many of the old pieces of machinery be 
ing got rid of, my engine is less bulky, a great deal lighter, 
much less expensive, and more durable than any other.— 
6. There is a very great saving of room in placing the en- 
gine within the water-wheel.—7. If there be a water-wheel 
on each side of the boat, with steam tubes extending to 
each, the boat may be turned about with great facility, by 
merely shutting the throttle valve belonging to the one wheel 
