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directions are perpendicular ; that is, the fum of 
the forces E and F will be to the power P, which fuf« 
tains them, as the fum of the (ides of the wedge to 
the bale, or as one fide to half of the bafej that 
is, as the radius to the fine of half the vertical angle 
of the wedge. Hence, when in cleaving timber the 
wedge fills the cleft, in which cafe the refinance of the 
wood aCts perpendicularly on the fides of the wedge, 
the power which drives the wedge muffc be to the 
cohefive force of the timber in a proportion fomewhat 
greater than that above mentioned, in order that it 
may divide the timber, whofe parts will then recede in 
lines perpendicular to the fides of the wedge. 
CASE II. 
Let now the refitting forces of E and F be fuppofed 
to aCt obliquely on the Tides of the wedge in the direc- 
tions E K and F Lj and let thefe forces be expretted 
by the lines E K and F L, and let each of them be 
refolved into two forces, expretted refpeCtively by the 
lines EG, G H, and F H, H L, whereof the forces 
G H and H L, by aCting parallel to the fides of the 
wedge, are loft : while the other forces, E G and F H, 
by aCting perpendicularly on the fides of the wedge, 
keep the power P in asquilibrio; therefore by the firft 
cafe thefe parts of the whole refitting force are to the 
power P, as radius to the fine of half the vertical an- 
gle of the wedge. But it is evident that the whole 
refitting force is to its parts expretted by E G, 
F H, as radius to the fine of the angle E KG, or 
F L H; and therefore (compounding thefe ratios) 
the whole refitting force will be to the power which 
luftains' 
