Impi-ovementt of the Simple Steam Engine. 425 



Tills engine -confumes fix bufliels of good coals in twelve hours* work when hi its bed 

 ftate, or feven bufliels when at the worft. Under thefe circumflances it gives ten ftrokes 

 per minute, each throwing out feven cubic feet of water, at an aperture twenty feet above 

 the water beneath. This quantity, namely 70 cubic feet per minute, will weigh 4345 

 pounds, which being doubled, to reduce it to Defaguliers's flandard heiglit of ten feet, will 

 amount to 8690. And this divided by 5S0, the number of pounds in a hogfhead, will give 

 a quotient of J5, reprefenting fo many men, according to the eftimate of that author, 

 wliich he reckons equivalent to three horfes. This refult is not more than half what is 

 performed by the improved engines with a pifl:on of fuch a fize as to be equal to 20 or 25 

 horfes. But how far thofe engines would prove efFe£tive upon the fmall fcale of three 

 horfes, or the ftill fmaller fcale of one or even lefs, remains to be decided. 



The engine here defcribed has been at work four years, and from the fimplicitv of its 

 conftruftion has yet exhibited no proofs of wear. Mr. Kier thinks it a profitable engine to 

 himfelf, and that it would be ferviceable for raifing water where coals are cheap. A con- 

 trivance he made in the year 1783 might, perhaps, with proper modifications, be ufed to 

 obviate the necefhtV of forcing where the heights are confiderable. It is liable, however, 

 to fome ftrong objeSions, and certainly requires to be maturely weighed with regard to 

 tjimenfions and effefts before it fhould be attempted to be put in praftice. 



Fig. 5. reprefents the contrivance for forcing, as I find it in the original drawing ; and I 

 thought it unneceflary to make any alteration to adapt it to what is called fucking, which 

 might, if required, be eafily done by any perfon (lightly acquainted with the fubjeft. A is 

 a boiler, and B a fteam-veflel. This laft communicates with the vefTels MLKT, each of 

 which, except the lower one, confifts of two vefTels ; an interior veflel, clofed on all fides 

 excepting where it communicates with B ; where pipes P, O, N, I, enter the upper part of 

 each ; and alfo where there is a valve at the bottom, opening upwards : the pipes I N O 

 likewife communicate with the three exterior veflels K, L, M. If fteam be let pafs from 

 A to B, it is inferred that the air will be driven from B, and prefs upon the water in the 

 lower veflel T, which will be driven into the exterior veflel of K, but not into the interior 

 veflel, bccaufe the preflure of the air through the tube H is more than fufiicient to keep 

 the valve of the apparatus K fliut. The next ftep in the operation confifts in clofing the 

 cock C, and opening D, out of which the re-a£lion of the water forcing itfelf into T to its 

 natural level, and into the interior veflel of K on the fame account, will drive a portion 

 of fteam. D is then to be clofed, and C opened ; in confequence of which, the contents 

 of T will be forced up to K, as before ; and the interior veflel K will evacuate its contents 

 into the exterior of L. The fteam being fliut off at C, and the cock D being opened as 

 •before ; the veflel T, the interior veflel K, and the interior veflel L will fill as before, and 

 a larger portion of fteam will iflTue from D. A third repetition of the procefs will drive 

 tlie contents of thefe three interior veflels a ftcp higher ; and a fourth repetition will caufc 

 the contents of the upper interior veflel M to flow out at P ; after which every alternation 

 of the work with the cocks C, D will throw out the fame quantity from P. 



I (hall only remark on this contrivance, ihat the veflel B muft neceflatily contain a quan- 

 tity of air capable of occupying the whole interior fpace contained in the clofed veflels 

 TK L M, with an allowance for the lofs of bulk in condenfation under the preflure of a 



Vol. I. — Declmber 1797. 3 1 column 



