Ward's Steam-Engine. 91 
vented a Revolving Engine, which, it was supposed, had 
completely triumphed over the difficulty of reciprocation. 
It may seem hardy to question a dogma, which has re- 
mained so long unquestioned ; but I hold it equally pusil- 
lanimous never to think ourselves at liberty to examine re- 
ceived doctrines; and I hope you and your readers will, 
therefore, excuse my presumption, in endeavouring to show, 
contrary to the received theory, that there is no loss of 
power in the reciprocating movement of the common steam- 
engine, and that the well known principles of mechanics 
have been applied to the subject, under a misconception of 
the facts. 
It is necessary, in the first place, to reduce to some 
more definite meaning, the phrases, ‘‘ dragging the inert 
mass in opposite directions,” and ‘‘ dragging it from a state 
of motion toa state of rest.” How and where does this 
“ dragging” take place? ‘The language here used, can only 
mean, that the power of the steam, being exerted upon the 
reciprocating mass, in a direction opposite to that, in which 
it ils moving, Overcomes its momentum, and causes it to 
stop. At what point, then, in the revolution of the crank, 
is the power of the steam thus exerted, and this cessation 
of movement affected? Supposing the crank to start from 
the upper dead-point, no such operation can take place at 
any point in the first half of the revolution ; for nobody ev- 
er disputed, that during this half, the power of the steam 
continues to be exerted, ‘and the reciprocating mass to move, 
in the same directions, which they respectively took at the 
commencement. ‘That such a cessation of movement can- 
not be effected in the other half of the revolution, that is, 
after the crank has passed the lower dead-point, is equally 
clear, from the same considerations. And if, therefore, it 
takes place at any point, in the whole revolution, it must 
be at the dead-point. 
Thus explained, then, the theory above mentioned, is 
this,—That, at the dead-point, the power of the steam, be- 
ing exerted upon the reciprocating mass, in a direction op- 
posite to that, in which it had been previously exerted, 
checks its momentum,” and causes it to stop. This 
proposition evidently assumes two facts: Ist. that, at the 
dead-point, the power of the steam is in full operation ; 
and 2ndly, that, at the dead-point, the reciprocating mass 
