342 Remarks on Mr. Quinby's Crank Problem. 
with a varying, as on one which meets with a uniform re- 
sistance, and also as much power in quantity ona piston, 
which meets with a resistance varying in the manner and ra- 
tio occasioned by the crank, as on one which meets with a 
resistance that varies in any other manner or ratio. Had I 
jeisure, I think I could exhibit satisfactory reasons why there 
is a great loss sustained betweer the piston and the boiler, by 
the use - the crank. But [ must leave this for another op- 
portun 
The Sah above proved with regard to the crank, may be 
exhibited ina manner entirely satisfactory to my mind, by 
another course of reasoning, which is of more extensive ap- 
plication ; and which shows, that, not only the crank, but 
every other species of machinery, which is, or may be con- 
trived, to modify power, or direct it to the pr oduction of an 
effect, will transmit that power, if it be all applied, without: 
loss in quantity, except the loss occasioned by friction, resist- 
ance of the air, changes in the form of the parts of the ma- 
chine, resulting from pressure or collision, and other adventi- 
tious causes. 
It is manifest, from the definition of power in degree and 
power in quantity, that mere pressure, or the effort of power 
in degree, can never occasion any expenditure of power in 
quantity. Thus the pressure of the steam on the internal 
surface of the boiler, ofthe cylinder and of the tubes by which 
it is conducted, occasions no — of its power, be- 
eause it is exerted in degree only : and so in numberless other 
eases. Now it will be ss Shad all power, which is ex- 
n the direction of the motion occasioned thereby, pro- 
cee tes fall and proper effect. And it is equally certain 
that a power which is exerted in a direction oblique to the di- 
rection of the motion which it —* may be resolved into 
wo components, one of which is in the direction of the mo- — 
tion, and the other perpendicular to it. This last compo- 
nent, being prevented by the construction of the machinery 
from producing motion, occasions no expenditure of the pow- 
er. Therefore all the power expended — directly, 
and consequently — its proper effect 
_~ From the preceding remarks, it will appear, that in me- 
fanies, when the term power, and other terms of similar i im- 
port,” are pied: without qualification, it is of great 
: they should be correctly understood, by considder- 
ing what species or measure of power the circumstances of 
