454 Mr. s me at on* on Mechanic Power. 
44 weight, which will keep it in equilibrio; but what it 
44 can move with the velocity it goes with, will be but 
44 one-third of that weight of equilibrium; that is,. T 4 T ths 
44 of the weight of the firft column, Sec. — This is the 
44 utmoft that can be expected.” 
The fame conclufion is likewife adopted by maclau- 
rin, in art. 907. p. 7 28. of his Fluxions, where, giving 
the fluxionary deduction of M. parent's propofition, 
he fays, 44 that if a repreients the weight which would 
44 balance the force of the ftream, when its velocity is 
44 a\ and u reprefents the velocity of the part of the en- 
44 gine, which it llrikes when the motion of the machine 
44 is uniform, See. — the machine will have the greatefb 
46 effect when u is equal to*; that is, if the weight that 
44 is railed by the engine be lei's than the weight which 
44 would balance the power, in the proportion of 4 to 9, 
44 and the momentum of the weight is 
Finding that thefe conclufons were far from the 
truth ; and feeing, from many other circumlfances, that 
the practical theory of making water and wind-mills was 
but very imperfedtly delivered by any author I had then 
an opportunity of confulting (*) ; in the year 1 7 5 1 1 began 
a courfe 
(a) belidor, Architecture Hydraulique, greatly prefers the application of 
water to an underfhot mill, inflcad of an overfhot; and attempts to demonfhate, 
that water applied underfhot will do fix times more execution than the lame 
applied overfhot. See vol I. p. 286. While desagulif.rs, endeavouring to 
invalidate what had been advanced by belidor, and greatly preferring an over- 
ihot 
