a eae

54 A N EF" St Sa“AF

confiderable weight of naturally heavy ma- terials upon them, added to. the preflure, of the beam, we may conclude, that the fric- tion of the wheels muft be very confidera- ble.. It would be a great diminution of this friGiion, if the diameter of the wheels were made double or triple in length what it is at prefent, which would diminith the fric- tion in the inverfe proportion: But this alte- ration would render it very inconvenient, if not impoflible, to turn the plough..

The only counterbalance I can figure in the common plough to thefe difadvantages, is, that the downward tendency of the ma- chine requires a weight to be laid on the backs.of the hindmoft cattle, which is not neceflary in the wheel-plough; becaufe this weight is fupported by the wheels.

I cannot eafily eftimate the amount of this difadvantage; becaufe it varies at dif- ferent times, according to the hardnefs, the ftiffnefs, or dirtinefs of the foil; but, from experience, it feems not to be very confide- rable; for the obliquity of the direction that produces it is not very great, and the cattle : expofed

a—

saa