ga 3 ENG BOS a

gentle curve. I found that it always turn- ed afide to the left of the direction of the force, pufhed the fand more before.it than the plain half-wedge, and was refiftedin a confiderably greater proportion than that of its furface. Hence it appears, that the wedge is the figure that meets with leaft refiftence, and confequently that the curved mould-board requires more force to pullit than the plain f.

There feems alfo to be great reafon to doubt, whether the curved mould-board per- forms better work than the plain. That it bruifes and feparates the foil more, mutt be admitted; but in the naturally loofe earth,

wherein it muft be ufed, this can be per- formed

+ It will perhaps be objeéted here, that this doétrine contradi€ts what Sir Ifaac Newton has ad- vanced concerning the folid of leaft refiftence 5 which is well known to be different from the wedge. But in anfwer, I beg leave to obferve, that that folid isa mere jeu d’ efprit, which prefented itfelf to its great author in the courfe of other inquiries, which neither he, nor any body fince his time, has at- tempted to apply to any ufe, and which probably never can be applied to any, at leaft it cannot to the

prefent fubject.