[ i6 7 3 
product of the fails laft-mentioned, at 121. feet in a 
fecond : therefore, by maxim 8th, if we multiply 
the fquare root of 19, that is 4,46, by 21 inches, 
the length of the fail producing the effedt 3 8(5 1 , we 
fhall have 93,66 inches, or 7 feet 94 inches for the 
radius of a Dutch fail in its bed: podtion,. whofe mean 
power (ball be equal to that of a man : but if they are 
in their common podtion, their length mufl be in- 
creafed in the ratio of the fquare root of 442 to that 
of 6,9, as thus appears;. 
The ratio of the maximum products of N° 8 and 
11. Tab. III. are 35442:639; but by maxim 8, 
the effects of fails of different radii are as the fquare 
of the radii ; confequently the the fquare roots of the 
products or effects, are as the radii limply ; and 
therefore as the fquare root of 442 is to that of 
639 ; fo is 93,66 to 112,66; or 9 feet 44 inches. 
If the fails are of the enlarged kind, then from 
Tab. III. N° 1 1 and 15. we ihall have the fquare 
root of 820 to that of 639: .'93,66 : 82,8 inches, or 
6 feet ic| inches : fo that in round numbers we Ihall 
have the radius of a fail, of a limilar figure to their 
refpedtive models, whofe mean power fhall be equal 
to that of a man ; 
The Dutch fails in their common pofition pi feet. 
The Dutch fails in their bed: poiition 8 
The enlarged fails in their bed: pofition — 7 
Suppofe now the radius of a fail to be 30 feet, and 
to be conftrudted upon the model of the enlarged 
fails, N° 14 or 15. Tab. III. dividing 30 by 7 we,, 
ihall have 4,28, the fquare of which is 18,3 ; and 
this, according to maxim 7, will be the relative 
3 power 
