Abstract: A single cavity specimen test tube carrier especially adapted to connect to like carriers along one axis or a different axis or in a matrix. The carrier includes a test tube holder, a viewing slot, a side-to-side coupling mechanism and a front-to-back joining mechanism to attach the carriers together along a specified axis or in a matrix. The side-to-side coupling mechanism includes a boss and boss receiving cavity which snap together in a force fit. The front-to-back joining mechanism includes a plurality of knob-like protrusions that fit snugly into the viewing slot of an adjacent carrier and a horizontal bar that slides under a corresponding ledge of the adjacent carrier.

Abstract: A connecting device is disclosed for electrically and mechanically linking multiple circuit boards arranged in two perpendicular stacks. The connecting device includes two identical connectors, each with a plurality of outwardly extended electrical socket contacts, and a pair of opposite, electrically insulative shoulders projected outwardly beyond the socket contacts. Electrical pin contacts are recessed into the shoulders. The pair of connectors can be engaged when in facing relation, with one of them rotated 90.degree. relative to the other. As the connectors are moved toward engagement, each shoulder of each connector enters into a nesting relation between the opposed shoulders of the other connector, pre-aligning the opposed pin and socket contacts. The shoulders have inclined edges at their outer faces, to assist in capturing their associated opposed shoulders and guide them, in a self-aligning manner, into the nesting relation. The connectors require a 90.degree.

Abstract: Apparatus for optical measurement of the displacement and the obliquity of a test surface relative to an imaginary reference surface. An inwardly converging ring of light is projected onto a test surface. An optical system conveys an image of this ring to a photo diode array where its circumference is compared to an imaginary image of the ring projected onto an imaginary reference surface. This comparison yields the displacement of the test surface through 360.degree. of rotation, which is converted into the shape or contour of the test surface.