475 
Steam Engines. 
Sly. A more certain mode as I think of discharging the air. It 
arises to the top of the water, and is thrown out by the valves that 
open with the upward stroke of the piston that throws the cooled 
water into the condenser. 
4ly. A new, and seemingly effectual method of keeping the wa- 
ter at a regular height in the boiler, by making the condenser dis- 
charge any surplus into the boiler. 
5ly. Savingand condensing the steam occasionally discharged 
from the boiler, and which in other engines escapes into the air, 
so that the boiler and condenser being once supplied with water, 
this stock of water is not diminished by waste steam, or encreased 
by extraneous injection water : or varied, except as need may arise 
from causes depending, not on the principle of working the engine, 
but from accidental and unavoidable imperfections and wear in the 
materials and workmanship, or perhaps from slight decomposition 
of the water itself. 
6ly. Boilers on a new, and if the workmanship can be depended 
on, an improved construction % not much differing in principle,v 
but greatly in form and arrangement from those hitherto employ- 
ed : being two large boiler-cylinders through which the fire flue 
runs, and which are furnished v/ith a series of pipes, and one small 
boiler-cylinder in the centre, over which is a cylindrical reservoir 
for the steam. 
71y. A rack, or cog-wheel with a handle, by which the ears 
or plugs, of the plug beam, may be moved and varied at pleasure ^ 
so as to regulate as need may require, the opening of two steam- 
valves, additional to the valves of the common engine : and by 
this means, to stop off the steam at any given point or portion. In 
Watt’s engine this is managed by a pin. By means of this regu- 
lator, if a fourth part only for instance, of the cylinder full, be 
thrown in, it can act by its expansive force. So that no steam need 
be employed, beyond what is necessary to the required work of 
the engine. The regulating valves, are on a construction differeni. 
from the common valves, being worked by rods, one v/itliin the 
other. The steam admitted, is also admitted at once, not gradu- 
ally; which last practice although recommended by Woolf and 
now common (see p. 186 of thisvol.) has disadvantages. 
Sly. A new method of augmenting the force of steam, hv ex- 
posing to considerable heat, a part of the steam that acts on the,, 
piston, and mixing it with the steam that proceeds direct from the 
boiler. Compare this with Mr= Woolf’s patent, page 190 of this 
Volume. 
