3-12 Patent for cerium Improvements 



bottom of their respective cylinders, the communications 

 between the boiler and the small cvlinder, between the 

 small cylinder and large cylinder, and between the latter and 

 the condenser, must all be shut- off; and the communica- 

 tions must he opened between the two sides of the smaller 

 piston and between the two sides of the larger piston : then, 

 as the pistons ascend, the steam which was last admitted 

 above the small piston will pass to its imder side, wiiile the 

 steam which was last 'admitted to the top of the large from 

 the lower part of the small cvlinder will pass into the lower 

 part of the large cylinder under its piston, and both pistons 

 will at the same time ascend bv the action of the counter- 

 weight, or the momentum of the fly, as the case may be. 

 When both pistons have reached the top of their respective 

 cylinders, the last-mentioned connnunications are shut, and 

 the others are opened as before, and both will descend; the 

 steam which was last admitted to the under side of the small 

 piston passing into the upper end of the large cylinder, while 

 the steam last introduced below the piston of the large cy- 

 linder goes off" to the condenser. Or an arrangement similar 

 to the following may be adopted : Let only the bottom part 

 of the smaller cylinder have a communication with the 

 boiler, and let there be also a communication between the 

 bottom of .the smaller and the top of the larger cylinder, and 

 another communication between the top part of both cy- 

 linders, which last-mentioned connnunication always re- 

 mains open ; and let the top and bottom of the large cy- 

 linder also communicate by means of a side pipe ; and 

 let the bottom part of the large cylinder communicate with 

 a condenser. Things being thus arranged, when steam is 

 admitting into the lower part of the smaller cvlinder, the 

 piston in that cylinder will ascend; the conmuuiication 

 between the top of the two cylinders bting then open, to 

 allow the sleain above the smaller piston to pass into the 

 top of the larger, where it is not to be detained, but, along 

 with the steam above the piston in the large cylinder, to be 

 allowed to pass under the last-mentioned piston (which is 

 now ascending as well as the piston in the smaller cylin- 

 der), the connnunication between the two sides of the large 

 piston being now open, and the communication with the 

 condenser shut off. Both pistons having reached the top 

 of their respective cylinders, the communications which 

 before were open must now be shut (excepting the com- 

 munication between the two cylinders at their upper part), 

 and the communications between the bottom of the small 

 and ihc top of the large, and between the bottom of the 



large 



