38 Rejoinder to Mr. Quinby on Crank Motion. 
Having already taken up more room than the subject 
demands, I will conclude with merely noticing Mr Quinby’s 
last paragraph. ‘This. setting aside what is personal and in 
the form of a challenge, appears a curious attempt to pass 
off a light proposition, by covering it with two of full weight 
and current value. He says *‘can the writer of the article 
in the Noth American Review invent a right angled [why 
right angled ?] plane triangle whose three angles shall not be 
equal to two ngit angles? Can he invent a steam-engine that 
shall be able to impart to the appending machinery more 
power than is applied? It is now established that all double 
stroke engines do impart to the appending machinery all the 
power that is applied, and consequently a saving of power can 
only be effected by the invention of a machine that shall 
impart more power than is applied to it ; and this, in the 
judgement of the writer of this reply, is not possible.” I 
object to the last paragraph, if Mr. Quinby means it to be 
understood in a general sense, and on the authority of 
Leans’ reports; I repeat that the rotary engine does not im- 
part at the working poitt, a force equal to that of the simple 
pum»ing engine through a long space of time (other things 
being equal) But perhaps Mr. Quinby means it only as 
another edition of the phrase “that the crank occasions no 
loss whatever of the acting power.” Taking it in this sense, 
however, I should yet Aesitate to make the conclusion which 
Mr. Quinby wishes to establish from it, namely that because 
in every triangle the sum of the three angle- is equal to two 
right angles; and because no machine can impart more 
power than is applied ; and because ‘‘ the crank occasions no 
cannot conceive how any one should suppose himself so well acquainted, 
not only with what the whole host of projectors have swpposed, but with 
what they have not supposed, as to make so round an assertion. So 
far as information is to be obtained from the specifications of the patents 
for inventions of this kind, it is very clear that a desire to get rid of the 
vis nertie of the working beam, and the constant variation of the 
mechanical advantage, which a force acting through a crank necessa- 
rily has; and likewise to make a more simple engine, have had great 
influence with the projectors of rotary engines. But it is enough to 
show the inacuracy of Mr. Quinby’s statement, to remind the reader 
that the engine of Brancas, that of Amontons, in both of which the force 
was applied to a wheel, and the wheel-engine of Mr. Watt, described in 
the 5th section of his specification of 1769; were all constructed and 
abandoned before the application of the crank to the steam-engine. 
