Abstract: A sample cell for use in spectrophotometry has a center-fed horizontal sample bore and exit ducts of reduced cross-sectional area leading away from the ends of the sample bore. In the disclosure, the cross-sectional area of the exit ducts increases downstream of the sample bore and the two exit ducts are joined by a horizontal bore parallel to the sample bore. The hydrostatic head of pressure downstream of the sample bore is minimized by arranging the outlet from the cell well below the inlet. The disclosed cell has low cross-contamination and drift figures, and is substantially immune from trapping of entrained bubbles even when used for discrete sampling.

Abstract: The adjustable error correction cam mechanism which defines the error signal necessary to compensate for inequalities in the attenuation of the optical paths of a twin-beam spectrophotometer is of the kind utilizing a closewound helix of spring steel wire whose outer periphery constitutes the cam working surface. The cam follower is of an improved design, being formed as a slider instead of a roller in order to provide the necessary accuracy of operation.