Abstract: Apparatus for containing a ferro-fluid within a reservoir of ferro-fluid using a pair of ferro-magnetic members adjacent each other and having opposing surfaces shaped as segments of surfaces of revolution, including magnetic apparatus for producing magnetic flux across the gap between the opposing surfaces. The surfaces diverge, and the greater magnetic flux density at the closely spaced edges of the pocket formed by the surfaces hold the ferro-magnetic particles of the ferro-fluid in that region. The volume between the two opposing surfaces is adequate to accommodate the thermal and pressure expansion and contraction of the fluid. The spacing between opposing members at the edge of farthest advance of the fluid is sufficiently small to allow the surface tension of the fluid to hold the fluid.

Abstract: An apparatus for positioning the target marker in a toss-bombing display to allow toss-bombing when the wings of the bombing aircraft are not level.