Cooper’s Rotative Piston. 319 
a ere discharge effected, by one and the same opera- 
tion, Asa further illustration of the point in question, it 
may be shearead 
a can be oo owe one naff. the power. 
hi 1s csapecsiiadl proof against frost. 
Those acquainted with the old engines, know, by sad ex- 
perience, the evils of frozen valves rae obstructed pistons, 
and that it is necessary to resort to me: hawing out the 
machine, or to suffer it to remain meloace? even at times of. fire. 
But a single revolution of the rotative, discharges the ice 
that may have collected on the surface exposed, and an ef- 
oe operation is not retarded for a moment. 
It discharges a more condensed column. 
It is apparent to the man of chemical science, if not to 
the common observer, that water, in the form of spray, 
and, 
instead of diminishing, increases its fury. The advantage of 
the rotative herein, as before observed, consists in dispensing 
with the air vessel. In the old machine it is indispensable, 
Yet, notwithstanding its use and importance to them, it con- 
stantly i imparts a portion of air to the water discharged, and 
thus far produces the evil complained of. 
* Giving its oxygen to the carbon, to increase its ignition, and its hydrogen 
to augment the volume of flame.—Editor 
