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"LIX. Description of a Rotative Steam Eagifie, the Piston 

 of which makes a complete Revolution at a Distance from 

 the revolving Axis. Invented by Mr. Samuel Clegg, 

 of Manchester. 



iVIany attempts have been made to produce a rotative 

 motion by means of steam, without deriving it from, or 

 making use of, the rectilinear motion of the piston in the 

 common or reciprocating engine. For this end steam 

 wheels and other contrivances have been resorted to, but 

 hitherto with little effect, owing to loss of steam, or to an 

 increase of friction produced by the means employed to 

 prevent this waste. Still a rotative steam engine appeared 

 lo promise so many advantages, could it be well accom- 

 plished, that some engineers continued to apply their 

 thoughts to the subject, and Mr. Clegg announces that he 

 has succeeded in producing a simple and effective engine 

 of this kind, for which he has obtained a patent. This 

 engine has no outward movements except the revolving 

 shaft, which occupies the centre and works through a stuff- 

 ing box in a cistern of water M; and which being the 

 only opening into the engine prevents the entrance of all 

 air excepting what is contained in the water used for in- 

 jection. The steam pipe is at P, and the air pump is within 

 the condensing vessel. The following is a description of 

 the engine : See plates XIII and XIV. 



Fig. 1 is the underside of a circular piece of cast iron, 

 and of a diameter and thickness proportioned to the size of 

 the engine. I is the common centre of the different circles 

 shown on this piece. With any convenient radius less 

 than that of A A describe the circle C C, and within the 

 latter the circles DDandEE — the radius of the latter 

 being the least of those now named. From the uses of 

 these parts, which will be immediately described, an ide^ 

 of their relative dimensions will readily be inferred. 



Let that part of the surface A B, A B which is contained 

 between the circles A and C be plain. Between the circles 

 C and D sink a circular groove CD of any given depth ; 

 and between the circles D and E let another circular groove 

 be cut of the breadth D E, and of any given depth less than 

 that of the groove C D. Let the remaining part of the 

 Surface A B, namely, that included between E and B, be 

 cut down to any depth less than the depth of the groove 

 DE. 



Into the groove C D let such a number of segments of a 

 Vol. 34. No. 140. Dec, 1809, Cc circle 



