Abstract: A device for compressing a pair of plates composed of a slotted post extending upright from one of the plates, arranged to pass through a port in the second of the plates, and a circular ramp member rotatably attached to the second of said plates, which ramp is positioned to engage the post slot. Upon rotation of the ramp, the post is drawn through the port resulting in a closing of the distance between or compression of the plates.

Abstract: A fluorometric titrator has means to transfer a pipette between first and second positions and a buret for a chelating agent has a reversible drive powered either by a pulse generator or an oscillator. Valve controlled means are operable to place the buret in communication with the pipette or a reservoir. In the first position of the pipette, a precise sample volume is aspirated into it by the buret, then driven by the oscillator and in its second position and with the buret drive reversed but still powered by the oscillator, the sample volume is discharged from the pipette into a cuvette in the fluorometer. On the resulting fluorescence the fluorometer output drives the pulse generator to dispense chelating agent and to operate a counter until a selected end point is reached. The pipette is then returned to its second position with the buret drive again operated by the oscillator and during the return, the buret is refilled.