Abstract: The invention relates to a vial located in a pocket in a carrier.The pocket has an upwardly opening inlet and a plane, bottom cam surface the vial has a complementary, plane, bottom cam surface. Both cam surfaces are inclined to the axes of the vial and pocket so that on lowering the vial into the pocket through its inlet, the cam surfaces interact so that when the vial is fully home in the pocket, it occupies a predetermined position of angular displacement about the vial axis.The carrier may be in the form of a turntable having a plurality of such pockets around the peripheral region of the turntable. The pockets may open outwardly from the center of the turntable through the peripheral surface of the turntable so that labels fixed and appropriately positioned on the vial walls are visible through the openings in the peripheral surface when the vials are fully home in their pockets.

Abstract: Specimen agitation apparatus comprises a horizontal turntable carrying, and its periphery, a plurality of substantially equally spaced vessels for receiving specimens to be agitated. The turntable is rotated stepwise about its central axis by a stepping motor which applies driving impulses to the turntable so as to cause it to rotate from a first rotational position to a second rotational position, but before coming to rest at the second position the turntable oscillates about the central axis to agitate the specimens.

Abstract: A device for use in producing a scanning beam of radiation comprises a rotor member carrying two optical wave guides arranged so as to direct light along the rotary axis of the rotor member, then radially outwardly to pass from one wave guide to the other, then radially inwardly and finally along the said rotary axis again.When the device is adapted for investigating liquid samples, a turntable, carrying a number of vials containing liquid samples at spaced locations around its periphery, is rotated in indexing fashion and, during each dwell period of the turntable, the rotor member is rotated so that the circularly scanning beam of light leaving the first mentioned wave guide scans each of the vials in turn at least once.