218 OUTLINES OF NATURAL PHILOSOPHY. 



the buckets may contain all the water of the stream, 

 and may carry it down as low as possible before 

 they allow it to escape altogether. 



309. If the section of that part of the wheel to 

 which the buckets are fixed be called c 2 , and the 

 perpendicular depth of the point where the water 

 leaves the wheel, below that where it enters, be 

 called p, the moving force is a column of water 

 equal to c 2 p ; and as this force acts by a lever = r 9 

 its momentum = 



310. If A fee the quantity of water issuing in a 

 second, and h the height corresponding to the ve- 

 locity of the circumference of the wheel, the ef- 

 fect of the machine, (supposing the wheel to re- 

 ceive the water, at or very near its highest point), 

 is proportional to A (2 r h). 



ALB. EULER, Enodatw Qutsstionis quomodo vis Aqua 

 ad Moilas circumagendas cum maximo lucro impendi 

 possit, 4to, Gottingen, 1754. BOSSUT, Hydrod. 

 415., &c. 



It is evident, that the effect will be the greater the 

 less h is, or the less the velocity of the wheel ; and 

 as that velocity may be diminished indefinitely, 2 r A. 

 is a limit to which the effect may approach nearer 

 than any given quantity. 



The power of the overshot-wheel is greater, cateris 

 paribus, than that of the undershot, nearly in the 

 ratio of 27 to 8. 



The 



