Abstract: An airborne cryogenic cooling system in which a first cryogenic material located within an on-board container is cooled to the solid state prior to launch a remotely located second cryogen conduited to the container. Immediately prior to becoming airborne connection is broken to the second cryogen and on-board cooling is achieved by venting the container to space environment causing sublimation of the solid first cryogenic, or, alternatively, the container may be left sealed and cooling results from triple-point transition of the solid cryogen.

Abstract: An educational apparatus for teaching subject matter relating to mechanics and for demonstrating a number of experiments. The apparatus, in kit form, consists of an assortment of balls of diverse properties, and a pair of upright, parallel, elongate members whose top edges, spaced from one another, provide a track for the balls to roll on. The track has the shape of a double declivity, symmetrically declining from opposite ends toward a center portion which smoothly joins the two slopes. A graduated scale is aligned with the track for the measurements of the distances traveled by the balls. Detents secure the balls at the top of each of the opposite ends of the track and are synchronously retractable by actuation of a remote electrical switch to release the balls simultaneously.