of Winds requijite to move heavy Wind Machines. 501 
the largeft kind. Now as the powers of limilar ma- 
chines, but of different magnitudes, are as their cubes, 
but the refiftance ariling from their weight and friction 
as the fourth power; it follows, that a fmall difference in 
the fize of two or more wind machines will require con- 
fiderable differences in the winds neceffary for their 
movements. 
I am, See. 
TABLE 
