22 A. WN EY. Sa a

This is the cafe in cleaving wood, or any folid body, where all the refiftence is gene- rally accumulated on{mall portions of the oppofite fides of the wedge.‘The circum- {tances are a little different; but the quanti- ty of force will likewife be found to be e- qual, in moving wedges of different incli- nations through fuch a loofe body as earth. In this cafe, as before, the longer wedge meets the refiftence more obliquely than the fhotter; but, to counterbalance this advan- tage, the refiftence acts a proportionally long- er time*, For, fuppofing both wedges to

move

confequently, if the back remain the fame, while the fide is increafed, the refiftance will be diminifhed in proportion. The fide indeed does not increafe quite fo faft as the length of the wedge does; but, when the difference between the half back and the fide is confiderable, as in the prefent cafe, it will do fo very nearly. Hence the refiftence in the fame {pace is diminifhed very nearly as the length in- creafes. And as the whole fpace is greater in that. proportion, the fum of the force in both cafes will be equal. * Let ABC, FHG, fig. 9. and 10. be two wed- ges of equal backs, AC, FG, but different lengths AB,