resistence

Hence it appears that the Curve MD cannot approach the Axis AL, then in the point D, where it Interſects the perpendicular AK; and that afterwards when AC is leſs then AE, then the Portion of the Curve DO, will be deſcrib'd Convex towards the Axis AL, ſo that the Surface of the Solid of leaſt Reſiſtence may be Concave as well as Convex towards the Axis.