[ 166 ] 
work at a mean rate : that is, by the compendiums 
in the laft article, when the velocity of the wind is 
8-| miles an hour, or 1 2-f feet in a fecond ; which, 
in common phrafe, would be called afreJJ: gale. 
The experiments fetdown in Tab. IV. N° 4. were 
tried with a wind, whofe velocity was 8 1 feet in a 
fecond ; confequently had thofe experiments been 
tried with a wind, whofe velocity was 12 3 feet in a 
fecond, the effect, by maxim 3d, would have been 
3 times greater; becaufe the cube of i2jis 3 times 
greater than that of 81 . 
From Tab. IV. N°4. we find, that the fails, when 
the velocity of the wind was 81 feet in a fecond, 
made 1 30 revolutions in a minute, with a load of 
17,25 ib. From the meafures of the machine, pre- 
ceding the fpecimen of a fett of experiments, we 
find, that 20 revolutions of the fails railed the fcale 
and weight 11,3 inches: 130 revolutions will there- 
fore raife the fcale 73,45 inches, which, multiplied 
by 17,52 ib, makes a product of 1287, for the effed 
of the Dutch fails in their bell; pofition ; that is, when 
the velocity of the wind is 81 feet in a fecond : this 
produd therefore multiplied by three, will give 3861 
for the effed of the fame fails, when the velocity of 
the wind is 1 2-| feet in a fecond. 
Defaguliers makes the utmofi: power of a man, 
when working fo as to be able to hold it for fome 
hours, to be equal to that of raifing an hoglhead of 
water 10 feet high in a minute. Now, an hoglhead 
confifiing of 63 ale gallons, being reduced into 
pounds averdupois, and the height into inches ; the 
produd made by multiplying thofe two numbers 
will be 76800; which is 19 times greater than the 
pro- 
