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exa(5tly in the middle or axis of the barrel, care was taken 

 that the pofition of the box, and of the focket annexed to it, 

 fhould be fecured, by having a prominent part of the plate 

 of the box of leathers inferted into the pump barrel, and a 

 like projedling part of the lid of the box inferted into the box 

 itfelf; alfo that the pifton rod Ihould mod exadlly fill the 

 focket in the lid. Over the collar of leathers, w^ithin the box, 

 lies a tinned brafs plate, which is prefTed down upon them 

 by the ends of three fcrews 3, 3, fcrewed through the lid of 

 the box. 



The pifton is moved up and down by the toothed flat bar 

 or rack F, whofe end is furnifhed with an arm G, (to be 

 taken off occafionally) which arm is fecured againft a fhoulder 

 formed on the end of the pifton rod, by a nut H fcrewed on 

 the I'od ; the rack is moved by a fmall fteel wheel L, one 

 inch and -/- in diameter, having twelve teeth, and which is 

 turned by the handle X fixed on its axis L. This wheel is 

 fuftained by the cheeks K, K, fig. J. & 2. furnifhed with 

 projcdling fockets, through which its axis paffes. Thefe checks 

 are fcrewed to the iron bar M, which is a part of the frame 

 fupporting the whole machine ; by this bar it is faftened 

 by clamps to whatever table it is placed on. From the 

 middle of the bar, and at right angles with it, extends ho- 

 rizontally an arm N, (rivetted and brazed upon the bar) the 



under 



