Doolittle on the Steam Engine. 101 
Art. 1X. Remarks on the Revolving Steam Engine of 
Morey, by Mr. Isaac Doonitrie. 
TO THE EDITOR OF THE AMERICAN JOURNAL OF SCIENCE, &e. 
Paris, 26th March, 1819. 
Dear Sir, 
Puysics and mechanics, especially when relating to 
American inventions, being my favourite studies, I eagerly 
seized the new revolving steam engine, invented by Morey, 
as described in the second number of your Journal; and, 
although the drawings, and description of its movements are 
very imperfect, I believe I understand its principles. 
The idea is ingenious, but I fear it will prove less useful 
than brilliant, for reasons which I will endeavour to explain. 
And first it may be proper to state, that the intensity or 
elastic force of the steam is altogether unimportant in the 
point of view in which I shall consider it; it is indifferent 
whether it be fifteen pounds or five hundred to the inch 
area ; as I shall only examine what portion of the force ap- 
plied to give the alternating motion to the piston is actually 
employed in producing the rotary movement of the cylin- 
der, and what portion is lost to all useful purposes. 
The enclosed diagram, Fig. I.* is a vertical section of the 
machine, (as I understand it from the drawings) perpen- 
dicularly to the axes of rotation. 
The portion of the force which is employed in producing 
a rotary movement varies at every instant with the angle of 
its application, and consequently has a maxymum and a min- 
smum. Its effect also, constantly varies with a perpetually 
varying lever at the extremity of which it is applied, the 
effect has therefore also a maximum and aminimum. These 
last are the only points at which it would be necessary to 
examine the machine in order to appreciate its comparative 
merits; but the points of maximum, depending on the two 
above causes, are not easily determined without having re- 
* The figures referred to by Mr. Doolittle will be found on one of the 
plates illustrating Mr. Sullivan’s Steam Boat. 
