Abstract: A base characterized by a substantially horizontally oriented plate adapted to receive a load, a vertically oriented post disposed beneath the central portion of the plate supporting the plate for pivotal motion about a plurality of horizontally oriented axes lying in the plane of the plate, and a pair of jack screws spaced ninety degrees apart and connected to peripheral portions of the plate, and a power train for selectively driving the jack screw, each independently of the other, for tilting the plate to achieve a leveling of a load supported thereby.