Improvement of Savtry's Steam-Engint. 413 



ferves as a key to open and (liiit the valve. NO is a ciftern of water, from which the fup- 

 p!y is made through the vertical pipe in which the valve Q^is placed ; and GG is another 

 ciftern into which the water is delivered through the pipe F, which is provided with a valve 

 H opening outwards. IM reprefents an overfliot wheel eighteen feet in diameter, moving 

 on the axis KL, and communicating its motion to the lathes and other rotatory engines of 

 the manufaftory. The water in both the cifterns becomes warmer than the hand after 

 working a fliort time ; for which reafon the injeftion-water is forced up by a pump from a 

 well fupplied by the fmall ftream on which thefe works are eftablifhed. A leaden pipe 

 pafles from this forcing pump to the upper or conical part of the chamber E, for the pur- 

 pofc of injefting cold water at the proper time. Neither of thefe could be reprefented with 

 convenience in the prefent feiSion. 



The manner in which the fleam and cold water are alternately admitted into the chamber 

 E, remains to be explained. Upon the extremity K of the axis of the overfhot wheel there 

 is fixed a folid wooden wheel about four feet in diameter, reprefented in fig. 3, as feen in 

 front, and alfo in profile, where the fmall letters denote the fame things as are marked by 

 the large letters of the alphabet in the front view. ABCD are four cleats, allor any number 

 of which may be fixed on the wheel at a time. Each cleat has its correfpondent block 

 EFGH on the oppofite furface of the wheel. The ufe of thefe is to work the engine. 

 Suppofe the wheel IM or any part of the revolving apparatus be drawn round by hand, one 

 of the cleats meets in its rotation with a lever which opens the fteam-valve by a bar of com- 

 munication reaching to the handle of the axis C, fig. 2. The fteam confequently pafles into the 

 chamber E, and the (leam-valve fhuts again as foon as the cleat has palled. Speedily after 

 this the correfpondent block on the other fide of the wheel meets another lever, which is 

 fimilarly attached to the handle of the forcing pump, and therefore throws a jet of cold 

 water into the chamber, and condenfes the fteam. The preflure of the atmofphere then 

 forces the water from the ciftern NO through the valve Qjowards the chamber E. Whea 

 the engine has been long out of work, I fuppofe two or three ftrokes may be neceflary to 

 r,iife the water to the top of the chamber. As foon as this is the cafe, the inje<£lion of the 

 fteam fuffers the whole body of water above the valve H to overcome the prefllire of the 

 atmofphere and rufti out. The water which is raifed is fullered to flow upon the overftiot 

 wheel through a fluice, and by that means keeps the work in motion, and replenilhes the 

 lower ciftern. 



Hence we fee that in effefl this engine is the fame as figure 1. excepting that it is not ap- 

 plied for the immediate purpofe of raifing water, but gives motion to other apparatus. It 

 is therefore unneced'iry to infift more largely upon the mere operation; but the peculiarities 

 of Mr. Kier's engine arc deferving of notice. In the firft place it may be obferved, that he 

 ufes no rcfervoir for his inje£lion water, but drives the requifite quantity up at each ftroke. 

 The advantage of this is, that the pump fuftains the adion of a very ftiort column of water, 

 though it apparently forces to the height of about %6 feet. For the columji in the pipe and 

 chamber I'E by its re-a<ftion t ikcs oft" the cfl'eft of an equal length of column which would 

 elfe have a£>ed againft the forcer, and thus rentiers the injeflion more eafy and quick. In 

 the fccond place it may be obferved, that he has proceeded direftly oppofite to the firft re- 

 mark of the Marquis of Worcefter, who rejc-£1:s drawing or fucking upwards. For this 

 engine does not force at all. Tlie water merely falls out of the ciianibcr, and confccjucntly 



never 



