322 - A. B. Q^uinby on Crank Motion. 



Note. — Since I wrote the above solution I have learned 

 that the N. A. Review contains an article in which it is sta- 

 ted that the crank motion occasions a loss of three fourths 

 of the whole power employed ! ! 



On relering to the article alluded to, (vol. 14, p. 407,) 

 I find the following statement relative to the loss of power 

 supposed io result frorp the reciprocating motion produced 

 by the crank. 



" There is in the steam engine a loss of power in chang- 

 ing the direction of its action from rectilinear to rotary, 

 bj> the methods in common practice, not very satisfactorily 

 accounted for, considering the magnitude of the loss, which 

 on an average amounts to about three fourths of the whole 

 power, as appears from the reports on the performance of 

 the engines used at the mines in Cornwall." 



"This, together with the hope of producing a more sim- 

 ple mach ne, has given rise to very frequent attempts to ap- 

 ply the action of the steam directly to a wheel, and by 

 that means obtain a circular motion primarily." 



With respect to the reports on the performance of the 

 engines used at (he mines in Cornwall, I have no knowl- 

 edge, end am, therefore, not able to refer to the authority 

 by which they were made out. 



It must, however, be concluded that a very great blunder 

 has, in some way, been committed by those who made the 

 estimates, since the reciprocating motion of the steam en- 

 gine does not in truth (abstractly considered) occasion any 

 loss whatever of the acting power. 



Any difference therefore between the effect produced by 

 the engines used at the mines in Cornwall, and the power 

 employed (to give them motion), must be refered to some 

 other cause than \\m\. of the reciprocating motion, which 

 has been imagined to produce it. 



In reference to the " very frequent attempts to apply the 

 action of the steam directly to a wheel," they have ever ap- 

 peared to me unnecessary and idle ; and, in my opinion, 

 they can never result either in emolument to the individual 

 engaged in them, or in advantage to the public. 



The steam engine, however, (in general terms,) is, doubt- 

 less, susceptible of further improvements ; and all attempts 

 to render its construction more simple, and especially to 

 generate steam at less expense, are highly laudable ; and 



