349 
Revolving Steam Engine. 
of the steam-boat, aaa the steam boilers, h h the tar vessels, to 
be afterwards described, c the valve box, d d the two cylinders 
seen in different aspects, e the piston rod, f the pitman, h the ^ 
centre piece, i i the shaft, k k the valves, 1 1 the steam pipes, 
m m the escape pipes, n n the condensers, 1 1 the water wheel, v v 
the face of the valves (in the small separate figures), and oo the 
tar fire. The frame which holds the cylinders, d d, is, by its 
opposite sides, hung so as to revolve. The centre piece /^, re- 
sembling a crank, is fixed to the end of the shaft or axis i, pro- 
jecting over the cylinder, and from this centre piece the bar or 
pitman f communicates with the cross piece of the piston rod. 
Two circular pieces or valves Ar, one of brass and the other of 
iron, are placed on the same axis i, but on the outside of the 
frame, one of them being fixed to the axis, and the other ac- 
companying the frame and cylinder in their revolution. From 
this last valve proceed the pipes I Z, which conduct the steam to 
each end of the cylinder. The valve has a smooth face, which 
is kept close by springs to the face of the other valve, which is 
fixed to the shaft. Steam pipes /3 /3 convey the steam from the 
boilers through the outer valve into the moving valve, and from 
the opposite side of the outer valve proceeds the eduction pipes 
o 0 , which lead to the condensers n p. 
These condensers are upright vessels (two of which belong to 
each cylinder), connected at top by a sliding valve-box, by 
which the steam is made to enter them alternately. They have 
two valves at the bottom, which are kept closed by weights. 
A stream of water is injected into the condensers, which escapes 
by the bottom valves by which also the air is blown out at 
every stroke, in which manner the engine is at first cleared of 
air. 
In order to give a reversed motion to the engine, two cocks 
and cross pipes are employed, for the purpose of changing the 
passage of the steam to the opposite sides of the valves. 
When the engine is thus constructed, the steam admitted be- 
low the piston by the lower pipe Z forces up the piston rod 
and the cross piece at its upper extremity. This cross piece 
carrying along with it the bar acts upon the crank A, v/hich 
thus gives a rotatory motion to the shaft i i, and of course to the 
VOL. I. NO. 2. OCTOBER 1819. 
A a 
