Definition of "slopewise"

The second member or part of the Plough, is called the skeath, and is a peece of woode of two foote and a halfe in length, and of eight inches in breadth, and two inches in thicknesse: it is driuen extreamly hard into the Plough-beame, slopewise, so that ioyned they present this figure.

1613, Gervase Markham, The English Husbandman‎