OF HYDRAULIC ENGINES. 16~, 



in the cylinder, it is found that no more than 8 pounds LECT. 

 of pressure must be allowed for, on every circular inch ^^^/-x 

 of the piston in the cylinder, that it may make about 

 16 strokes in a minute, about 6 feet each. 



Where the boiler is very large, the piston will make 

 between 20 and 25 strokes in a minute, and each 

 stroke 7 or 8 feet ; which, in a pump of 9 inches bore, 

 will raise upwards of 300 hogsheads of water in an 

 hour. 



It is found by experience that a cylinder 40 inches 

 diameter, will work a pump 10 inches diameter, and 100 

 yards long : and hence we can find the diameter and 

 length of a pump, that can be worked by any other 

 cylinder. 



For the conreniency of those who would make use 

 of this engine for raising water, we shall subjoin part of 

 a table calculated by Mr. Beighton, shewing how any 

 given quantity of water may be raised in an hour, from 

 48 to 440 hogsheads ; at any given depth, from 15 to 

 100 yards : the machine working at the rate of 16 

 strokes per minute, and each stroke being 6 feet long. 



One example of the use of this table will make the 

 whole plain. Suppose it were required to draw 150 

 hogsheads per hour, at 90 yards depth ; in the second 

 column from the right hand, 1 find the nearest number, 

 viz. 149 hogsheads 40 gallons, against which, on the 

 right hand, I find the diameter of the bore of the pump 

 must be 7 inches ; and in the same collateral line, under 

 the given depth 90, I find 27 inches, the diameter of 

 the cylinder fit for that purpose. And so for any 

 other. 



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