Mr. smeatoN oh Mechanic Power . 47^ 
dicular, being, as has been fhewn, a given mechanic 
power, let me expend it at what ratelwill, if when this is 
expended, I muft wait another hour before it be renewed, 
by the natural flow of a river, or otherwife, I can then 
only expend twelve fuch quantities of power in 24 
hours ; but if, while I am expending 1000 tuns in one 
hour, the ftream renews me the fame quantity, then I 
can expend 24 fuch quantities of power in 24 hours; 
that is, I can go on continually at that rate, and the pro- 
duct or effect will be in proportion to time, which is the 
common meafure; but the quantity of mechanic power 
ariflng from the flow of the two rivers, compared by 
taking an equal portion of time, is double in the one to 
the other , though each has a mill, that, when going, will 
grind an equal quantity of corn in an hour. 
/ 
Vol. LXVI. 
R r r 
XXVIII. Anew 
