Rotatory Hydraulic Engine. 467 



oppofite lines, where the place of contafl. is made water tight by leathering, packing, or 

 any of the ufual methods. At oppofite parts of the furface of the cylinder are two flaps 

 C, C, which are urged outwards by fprings, which caufe them to bear againft the interior 

 furface of the ellipfis, and when prefled down they fall into cavities in the cylinder, fo as to 

 complete the defe£live portion of its face. It muft be underftood that thefe flaps, as well 

 as the cylinder itfelf, are of the height to fill up the interval between the flat faces of the 

 top and bottom, and are fecured fo as to be water tight. Laftly, E E are two pipes lead- 

 ing downwards to the water intended to be raifed, and F F are two pipes leading upwards 

 to the refervoir, or receptacle, to which it is to be conveyed. The firft. mover is applied 

 at the extremity D of the axis. 



The action. Let us fuppofc an engine of this conftruQion to be fixed on board a (hip 

 centrically beneath one of the capftans, and that by the common contrivance of a gear bar, 

 or other equivalent piece, the lower extremity of the axis of the capflan is connected with 

 that of the machine, and a convenient number of men fet to work it in the direction H G. 

 The immediate confequence will be, that the fpaces H, H, behind the flaps C, C, will be 

 enlarged, and as they are air tight, the prefiure of the atmofphere will drive water from 

 the well through the pipes E E into thofe fpaces. As the flaps C proceed towards F, they 

 will be prefled in by the elliptical concavity, and at laft the fpaces GG will difappear, and 

 the greateft part of the fpaces H H (then conflituting the whole internal part of the veflel) 

 will be nearly full of water. By the continuance of the procefs the two flaps will have 

 paflTed the places of contadt, and begin to open on the oppofite fides of the ellipfis, driving 

 before them the water and air up the pipes F F ; at the fame time that the fpaces H H be- 

 come again enlarged, and draw a frefli fupply of water through E, E. A conftant and 

 almoft equable dream is thus produced through the apparatus, which has this advantage, 

 that by increafing the number of men at the capftan, the velocity of this current may be 

 increafed, fo as to equal, as it fliould feem, any exigency the (late of the veffcl might 

 produce. 



If the fuflion pipes were occafionally led into the fea, and the forcing pipes into a 

 moderate Gzed air veflel, like that of the fire engine, a very powerful ftream of water might 

 be diredted to any part of the (hip, in cafe of the dreadful accident of fire; or for the 

 common purpofes of cleanlinefs of the births of men or animals, upon which fo much of 

 their health and comforts depend. 



Shall I extend my fpeculations farther, and exprefs mf conje£lure, that this might form 

 no contemptible fteam engine, if fteam were admitted through E into H, and condenfed 

 fo as to render the preflure of the atmofphere a£live in G upon the flap, when the conden- 

 fation were made ; or that it might receive the action of a defcending ftream of water, 

 and work a mill, or other ufeful machine, &c. &c. Or (hall I not rather leave this vl- 

 fionary region of fanciful indulgence, and commit the fate of my engine at once to the 

 cenfure or praife of yourfelf and readers ? 



O.B. 

 3 O 3 *#* Many 



