[Nsspampgsql-devel] be done is to throw

[Towsley]

Great velocity of their motion? _A._--Not if they are properly constructed; but they require to be much stronger, to be fitted with more care, and to have the bearing surfaces much larger than is necessary in engines moving slowly. The momentum
of the reciprocating parts should also be balanced by a weight applied

to the crank or crank shaft, as is done in locomotives. A very convenient arrangement for obtaining surface is to form the
crank of each engine of two cast iron discs cast with heavy sides, the excess of weight upon the heavy
sides being nearly equal to that of the piston and its connections. When the piston is travelling in one direction the weights are travelling in the opposite;
and the momentum of the piston and its attachments, which is arrested

at each reciprocation, is just balanced by the equal and opposite momentum of the weights. One advantage of the horizontal

engine is,
that a single engine may be employed, whereby greater simplicity of the
machinery and greater economy of fuel will be obtained, since
there will be less radiating surface in one cylinder than in two. CYLINDERS,
PISTONS, AND VALVES,
443. _Q._--Is it a beneficial practice to make cylinders with steam jackets?

_A._--In Cornwall, where great attention is paid to economy of fuel, all the engines are made with steam jackets, and in some cases a flue winds spirally round the cylinder, for
keeping the steam
hot. Mr. Watt, in his early practice, discarded the steam jacket for a time, but resumed it again, as

he found its discontinuance occasioned a perceptible
waste of fuel; and in modern engines it has been found that where a jacket
is used less coal is consumed than where the 
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