Description nf a Rotative Si earn -Engine. 403 



is in fact a recess in the deeper groove C D, and may, if 

 necessarv, be filled with hemp and tallow, or any other 

 material which may answer the purpose intended. 



It must be remembered that fig. 1 is a view of the un- 

 derside of this machinery. Figs. 2 and 3 are sections of it, 

 supposed to be in its proper position resting as a cover 

 to the circular chamber Y Y, and the segments resting 

 npon a flat facing O 0. Each segment projects over the 

 facing O O on both sides ; their projection on one side 

 completes the cover over the hollow chamber, and the other 

 is the rounded surface for the roller to Hit tliem. 



The facing O O is exactly, or as nearly as can be, level 

 •with the vmderside of the plate A B, AB, when the plate is 

 on its place, as represented in fig. 2 ; so that, when the 

 segments are all in their places, they complete the serai- 

 circular chamber, and fit so close on their seats and in the 

 groove, that were the chamber to be filled with any elastic 

 fluid, they would prevent its escape (or nearly), excepting 

 where the space is left for the sprins^s or adjusting screws. . 



The use of these segments, which are what the patentee 

 claims as his invention, is as follows : Conceive a door or 

 valve to he fitted in the hollow chamber at O, and a piston 

 R, likewise fitted in the chamber so as to move round in 

 it, and the bar F made fast to the piston, on the side and 

 in the manner represented in fig. 1 : then, if an elastic 

 fluid, of sufficient strength^ enters the chamber at N, it 

 will press equally against the door or valve and tlie piston ; 

 but the door or valve being immoveable, and the piston 

 moveable, the piston will be propelled forward in the cir- 

 cular chamljer by the elastic fluid. The bar F being fastened 

 to the piston, and the roller G to the bar F in ttie manner 

 represented in fig. 3, and the roller being in motion with 

 the bar and piston, the roller will lift the segments in suc- 

 cession, as it comes in contact with them. The segments 

 before the bar, being by this means lifted, allow the bar to 

 pass, and the operation being the same in all, the bar ami 

 piston make a complete revolution. Each segment, a* 

 soon as the l)ar leaves it, falls down by its own gravity, or 

 by spiings, or any other contrivance,, so that the opening 

 which has been made for the bar to pass is closed before 

 the elastic fluid reaches it ; the elastic fluid being kept fromi 

 the opening by the inner breadth of the piston exceeding 

 the outer diameter of each segment. The door or valve is 

 lifted out of the way of the pi->ton, when the piston cornea 

 iu contact wiili it, uUo the opening in tiic plate at N, a rc- 

 C c 2 cess 



