106 Sullivan on the peer ia: Engine. 
Arr. X. Mr. Surtivan on the Revobiinji Engine ; in re- 
ply to Mr. Dootirrus.* 
TO PROFESSOR SILLIMAN. 
Sir, 
7 WAS so yeas hdpaty of the inadequacy of my descrip- 
tion of Morey’s Steam Engine in your second number, that ~ 
I had yee os Nine of eiforive a supplement, when i 
gave an opp portunity of reading the remarks o 
Doolittle, which [ presume you will insert, mre this 
further explanation. 
The invention was then quite in its infancy, and your 
American readers will require no apology for occupying a 
page of your Journal once more, with a subject perhaps in- 
teresting only as it relates to the developement of the re- 
sources of our country: this form of the yan de pe- 
culiarly adapted to canals and other inland na 
Referring to the annexed plate and ea neebinoed I will 
pie attempt to suse the remarks of your correspon- 
“The objection ‘that a part of the force is lost in producing 
a rotary motion, applies, I think with equal propriety to 
all engines communicating by the intervention of the crank 
—as in all of them it must be considered as a varying lever. 
By loss of force must be meant the difference between the 
effect j it would produce were its action always at right an- 
gles to the crank, and its indirect action, as it revolves. 
Professor Playfair estimates this difference as 7 to 11— 
at is, a rota ay motion is produced by the crank at the 
expense of ;‘ths of the power which the engine would have, 
could i it be baerted directly upon its object, or load. This 
mate of loss relates to atmospheric engines. 
Nospithmanding this however, it was Considered a a great 
improvement when Mr. Watt introduced the crank. It gave 
the steam engine to many more useful purposes ; though 
mark.—The temporary suspension of the Journal offered mean oppor- 
tunity of submitting Mr poreks 7 s remarks to Mr. Sullivag’s perusal, which . 
gives these gentlemen the mutual advan oeauel having “age pres — 
together, instead of oom Sati in different numbers. — 
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