Abstract: In a photometric solution analyzer of the rotary type wherein a carousel includes a multiplicity of improved cuvettes, the carousel being journaled on a shaft driven by a motor, the analyzer further including means for permitting transfer of radiant energy from a source thereof to a detector therefor along an optical path passing through at least part of each of the cuvettes, the cuvettes being disposed about the carousel for receiving and mixing a reagent and a sample, each improved cuvette comprising a sample holding means being disposed in each cuvette for receiving the sample, the sample holding means being located radially outward from the center of the carousel, and a chamber being disposed for receiving the reagent, the chamber being located below the sample holding means and radially inward of the sample holding means, the chamber further being disposed in the optical path so that radiant energy is passed therethrough, whereby rotation of the carousel causes the reagent in each cuvette to flow towards

Abstract: A turntable is supported upon a support base and is urged rotationally through step increments at a constant stepped rate. The step rotation is accomplished by an air actuated ratchet mechanism. Peripheral depressions are provided for accepting a plurality of cuvettes for holding samples and reagents spaced apart within the cuvettes. A depending member on the cuvette is configured for contact by an air actuated extension arm for rocking the cuvette in its peripheral position on the turntable for mixing the sample and reagent. The extension arm is adjustable rotationally to contact the depending member on a cuvette at a predetermined rotational mix position on the turntable. A rotational reference position for the turntable is defined on the support. A predetermined time is thereby selected for reaction between the sample and the reagent dependent upon the selection of the mix position and the constant stepped rate of turn imparted to the turntable.