of Winds requifite to move ■ heavy Wind Machines. 499 
cietv, much converfant in thefe matters, I had the fatif- 
faCtion to find that he thought them worthy to be 
communicated to the Royal Society ; but remarked, that 
the materials, which I had proceeded upon, were not fo 
applicable to the purpofe as could have been wifhed. 
He thinks, that the degrees of winds, being only dif- 
tinguifhed into four in the journals from whence thofe 
tables have been compiled, are much too few to take in 
thofe of the weaker kind, that will however turn well- 
conftructed wind-mills. Indeed I regretted that the table 
from which I made my eftimate contained fo few de- 
grees; but it was for that reafon I calculated an inter- 
mediate degree between the fecond and the third of our 
meteorological regifter. Now as all the degrees above 
that intermediate degree are fufficient to move the hea- 
vieft machine, and the degrees below it infufficient for 
that purpole, fo far as I have been able to obferve, it 
comes to be the fame as if the table, from which I made 
the eftimate, had confifted of eight degrees, fuppofing a 
mean proportion to be found between the other degrees : 
thus, o, j, 1, iy, 2, 2y, See. this laft number 2y, being 
the loweft degree which I find fufficient for the heavieft 
machines, would have been 5, had thefe fractional parts 
been integers in the table, fo that the higheft degree, in- 
ftead of 4 would have been 8. The mean, therefore, 
T t t 2 between 
