Steam Engine. 201 
aa» The steam-pipe, through which the steam is con« 
veyed from the boiler to the receiver. 
h. The feeding-pipe, for supplying the boiler with hot 
ccccc. The condensing apparatus. 
dd» The pipe which conveys the hot water from the 
condenser to the hot- well. 
eee. Valves for admitting and excluding the water. 
ff. The injection pipe, and g the injection cock. 
h. The condenser. 
It does not appear necessary to say any thing here on 
the manner in which this machine performs its operations 
-without manual assistance, as the method of opening the 
cocks by which the steam is admitted into the receiver 
and condensed, has been already well described by seve= 
ral writers. But it will be necessary to remark that the 
receiver, penstock, and all the pij>es, must be previously 
filled^ before any water can be delivered on the wheel, 
and when the steam in the boiler has acquired a sufficient 
strength, the valve at c is opened, and the steam immedi- 
utely rushes from the boiler at E into the receiver A, the 
water descends through the tubes A and B, and ascends 
through the valve e and the other pipe or tube B into the 
penstock C, This part of the operation being performed 
and the valve c shut, that at a is suddenly opened, through 
which the steam rushes down the condensing pipe c, and 
in its passage meets with a jet of cold water -from tlie in- 
jection cock g\ by which it is condensed. A vacuum 
being made by this means in the receiver, the water is dri- 
ven up to fill it a second time through the valves ee^ by 
the pressure of the external air, when the steam- valve at c 
is again opened, and the operation repeated for any length 
of time the machine is required to work. 
^ Or the air blown out by- steam ; which may perhaps be less 
convenient than the method in the text.-— >N. 
Voi. II. e c 
