The surface exhibits a series of smooth rounded hills, and undulating ridges, separated from each other by deep valley-like ravines-the concavities of the latter so resembling the Convexities of the former, as to suggest the idea that the hills have been scooped out of the valleys, and placed in an inverted position beside them.
"The White Gauntlet"
Mayne Reid
If it is a question of light, then in all but absolutely transparent masses, the outer parts must undergo more of any change producible by it than the inner parts-supposing other things equal; by which I mean, supposing the case is not complicated by any such Convexities of the outer surface as produce internal concentrations of rays.
"Essays: Scientific, Political, & Speculative, Vol. I"
Herbert Spencer
To re-establish the equilibrium of the column, "secondary" or "compensatory" curves, with their Convexities to the left, develop in the regions above and below the primary curve.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition."
Alexander Miles Alexis Thomson