92 Ward's Steam-Engine. 
ssesses momentum, and indeed, all the momentum, which 
the power of the steam could give it, in the semi-revolution. 
Both of these assumptions, [ undertake to 
1. In their speculations on — this anhjecty: philosophers 
seem to have overlooked the mode, in which a steam-en- 
gine must necessarily be made, if intended for any useful 
purpose. Itisofthe very essence of its construction, t at 
not a_ article of steam can enter the —: when 
ria seaciie founded in the very nature of sit that 
no power can be reversed, in its direction, as it is here; 
without first ceasing to act? And, as the power of steam 
is confessed to act, both before and ten the crank arrives 
at the dead-point; where else can it cease to act but at the 
oo or which is the same thing, the point of its re- 
on ?—At the dead-point, therefore, the Bngine must 
be 16 poutonaly pode ser 
2. The disproof of the second assumption seems to:fol- 
low, asa corollary, from that of the first. It is acknowl- 
edged by all, fiat the reciprocating mass does stop at the 
dead-point ; and what is this, a pict mode of saying, 
that it has ceased to have mome 
If, then, the momentum of did scmeeiinion mass be not 
overcome by the aig bee of the steam, how, and by what, 
isit overcome? ‘Th explanation of these points will 
be found in the connexion of the fly-wheel with the recipro- 
cating ser by means of the crank. Supposing no other 
inert body to be connected with the Engine,—since we have 
just seen, that the momentum of the reciprocating mass 
cannot be overcome by the power of the steam, of course, 
there is nothing else which can overcome it, but the iner- 
tia of the fy-whee. And the modus operandi, L take to be 
iprocating mass and fly-wheel being con- 
ium of the crank, it results, from 
1e accumulation commences, and continues gradu- 
alley nti it arrives at its maximum. Now, during the re-_ 
