On the Priiicipks of Pur.ip-jrurk. 229 



no such application of the b;u-rc!s to the jiipe in tlieni, a,'* 

 cip)}cars in mine, where the course of the water from the 

 pipe is directly into each barrel; hut in theiu it is very 

 oblique, and the force of the water must he greatly broken. 

 3. None of these double-barrelled pumps have. piston;:;, like 

 those in mine, \\iihout friction. 4. The leathern piston 

 above mentioned was applied to -a single pun)p, and not in 

 a double one, as in mine. 5. This leather piston was of a 

 different form from mine, and admitted of but a very short 

 stroke. 6. Not onlv the construction, or application of the 

 parts of this pump is very diff"erent from that of all others, 

 and their essential defects thereby removed ; but it is at- 

 tended with many circumstantial advantages which cannot 

 fail of recommending it to all who have occasion for a ma- 

 chine to raise u atcr. 



The great velocity and force with which the water rises in 

 the pipe, carries up every thing that lies in the way, asheavy 

 nieces of iron. Sec; therefore it is plain it can be no ways 

 liable to be choked as othur pumps are too often, as is well 

 known bv fatal experience. 



One thing here is of too great importance not to be 

 mentioned, viz. that whereas in common ])iunps a fissure or 

 crack in the watci-pipc, by which the air can get in, stops 

 the operation of the pump entirely ; in this pump, if the 

 fissure he not vcrv laroe, tlie water will continue to rise, as 

 we have experienced by making a hole in the said water- 

 pipe 1-fourth of an inch wide. An efiect, I believe, never 

 before heard of in pump-wor'.:. 



The structure of this pump is so verv simple that it can- 

 not be often out of order; and when it is, it may be rectified 

 in a verv short time, without anv difiiculty or trouble. 



And a peculiar advantage in this pump is, that while one 

 piston is mending, the other may be kept working; and how 

 great a succour and relief this nmst afford to the dejected 

 mariners in a leakin^r ship, they best can tell whose lives 

 have been deeply endangered bv an unavoidable cessation of 

 the operation of the pump. 



This pump may be made of a>iy size, and constructed 

 with an air-vessel, as in the common stream engine f<jr 

 putting out fire; n)av bt wrought wJh men, water, wind, 

 horses, Sec. for all the purposes of raising water to supply 

 reservoirs, cxlincuish fires, water gardens, (jvaeuate ponds, 



[To be conrinujd ] 



P3 XLI. Ev^ 



