bottomward

According to one expert analysis in "The Physics of Skiing," a 176-pound skier plunging bottomward at 63 mph in a photogenic crouch experiences aerodynamic drag of 39 pounds, vs. snow friction of only 7.

The sea-wolf bare then, when bottomward came she, She grabs him, and bears him to her den.

The most noticeable peculiarity of this species of craft, and a remarkable one it is, is a decided and chronic inclination to turn its bottom side upward and its upper side bottomward without the slightest apparent provocation.