197 
Steam Engine* 
lion pipe that leads to the condenser. Two of these open- 
ings are alternately connected together by a slide valve, ^ 
while the third is left open for the admission of steam to 
the piston, this valve changes its position at the end of each 
stroke of the piston, and performs all the purposes of the 
most complicated machine. 
H. The air-pump connected with a condenser at tlie 
bottom of the eduction pipe. 
I. The fly wheel fixed upon an axis which receives^ 
its motion froi-ma crank connected with the beam by the 
rod K.- 
LL. Two rods for connecting the motion of the pis- 
ton to the beam, these rods move perpendicularly by a 
motion which could not be conveniently shewn in tliis 
view without rendering it confused. 
M. A spherical triangle turned by the crank for mov- 
ing the slide valve by the horizontal rod N that connects 
them together. This motion has tlie advantage of pre- 
venting the engine from ever turning the contrary way 
round from that which it is wanted to gOj and prevents 
the noise that is usually heard in engines. 
O. The beam attached to the bottom of the cistern 
C by means of the hanging carriages P. 
Q. A rest or fixture in a wall for the end of the fly wheel 
shaft ; this will vary according to the situation where the 
engine is to be fixed, or it may be supported by a metal 
standard. 
R. Index to the injection cock that admits water to 
the condenser. Note^ The cistern is to be kept nearlv 
full of water during tlie time the engine is at work. 
The cylinder G and valve box E must be surrounded 
on all sides by a case, (not shev/n in this view) the space 
between filled with charcoal to prevent the transmission 
pf heat, which if effectually done will work with the least 
* For these valves I took out a patent in ! 802 / 
