228 MACHINERY IN CONNECTION WITH WATER. 



pipe will bear.* The greater the height, in proportion to 

 tlie fall of the stream, the less will be the quantity of wa- 

 ter elevated, as compared with the quantity flowing in 

 the stream, or escaping from the waste valve. 



H. L. Emery gives the following rule for determining 

 the quantity of water elevated from a stream ; ^Divide 

 the elevation to be overcome by the fall in the drive-pipe, 

 and the quotient will be the proportion of water, (passing 

 through the drive-pipe), which will be raised, deducting, 

 also, for waste of powder and friction, say one-fourth the 

 amount. Thus, with 10 feet fall, and 100 feet elevation, 

 one-tenth of the water would be raised if there w^ere no 

 friction or loss ; but, deducting, say one-fourth for these, 

 seven and a half gallons in each hundred gallons 

 would be raised, the rest escaping, or being required to 

 accomplish this result. Or, if the fall of the water in the 

 supply-pipe be 3 feet, and the elevation required in the 

 discharge-pipe be 15 feet, about one-seventh part of all 

 the water will be elevated to this height of 15 feet. But 

 if the desired height be 30 feet, then only about one-four- 

 teenth part of the water will be raised ; and so on in 

 about the same ratio for different heights. A gallon per 

 minute from the spring would elevate six barrels five 

 times as high as the fall, in twenty-four hours, and at the 

 same rate for larger streams. With a head of 8 or 10 

 feet, water may be driven up to a height of 100, or even 

 150 feet, provided the machine and pipes are strong 

 enough. The best result is obtained when the length of 

 the drive-pipe and the momentum it produces are just suf- 

 ficient to overcome the reaction caused by the closing of 



* When water is raised to a considerable elevation by means of the 

 water-ram, the reservoir must possess great strength. If the height be 

 100 feet, the pressure, as shown on a former pat;e, is about forty-four 

 pounds to the square inch. With an internal surface, therefore, of only 

 2 square feet, the force exerted by the column of water, tending to 

 burst the reservoir, would be equal to more than twelve thousand 

 pounds. 



