THE WATER RAM. l09 



. •■ • ■ • -fett,- 



The same of sheet lead » 50. 



A pipe of cast iron, two inches in diameter, and J -3d 



of an inch thick, at least 500. 



A pipe of elder, an inch and half in diameter and 



two inciies thick y 30 or 40. 



I have seen pipes of this kind however constantly supporting 

 the pressure of a column of water of IJO feet. 



From tliesc data it will be very easy to calculate the proper Ascending 

 thickness of the ascending pipe according to its diameter, P'?^* 

 which should be the same throughout its whole length. If it 

 be necessary to make turns in it, tiiey should not be too sharp ; 

 for the water will move in them with more facility, the more 

 gently the alterations in its direction are made. 



It is obvious, that, when water is to be raised to a very 

 great height, the asc>3nding pipe does not require the same 

 thickness throughout its whole length. The greatest thickness 

 is requisilc only for the lower part, the pressure diminishing 

 as the column of water shortens ; the thickness therefore may 

 be gradually diminished also, ciilculating wiiat is required at 

 different heights according to the rule above given. 



Having now given a sufficient description of this new 

 machine, to make it known to those who may have occasion 

 for such a one, it will be proper to speak of the expence at- 

 tending its construction. 



This, as may be supposed, is very variable, as affected by ^'^'Pence of 

 , . '....-- . constructiorw 



the circumstances oi its situation, liowcver we may say in 



general, that the expencc is proportional, 1st, to the quantity 

 of water to be raised ; 2dly, to the height to which it is to be 

 conveyed; 3dly, to the distance from the reservoir ; 4thly, to 

 the fall of water, as the expence will be greater in propor- 

 tion as this is less. 



An example will give a more accurate idea of the expence of One of 4 inches 

 the machine. The object was, to raise to the height of 108 fcct]^^^^^, l8o1"eet 

 the greatest quantity of water possible with a fall of 4 feet 9 with a fall of 4 

 inches. For this purpose a ram of 4 inchoe diameter waS ^^ i-'ic^eb, 

 employed, which expends nearly 11,500 cubic feet of water a 

 day, and in that time raises nearly QAO cubic feet to the height 

 rcqiiired. The ascending pipe is J)00 feet long. The ram 



properly 



