Abstract: The invention contemplates instrumentation to enable performance of a plurality of automatic photometric analyses upon liquid samples, as in different analyses of such body fluids as blood, urine, etc. Prior to photometric evaluation, the liquid samples are automatically subjected to controlled doses of one or more reagents, and dwell times, as appropriate to the analysis to be performed at any given time. The particular automatic performance of a given analysis is supplied from an insertably replaceable holder which contains the reagents, dosage devices, and program-control coding unique to the particular analysis. Upon inserted replacement of the holder with another selected holder which is suitably encoded and equipped with reagents, the same instrument will serve for the handling of liquid samples unique to a different biological analysis.

Abstract: The invention contemplates continuous monitoring of a sample solution for cloud disturbances while conducting absorption-photometry measurements on the solution. The absorption-photometry measurements are a function of light directly transmitted through the sample solution, and the cloud disturbances are observed to the extent that the same light is or may be dispersed by cloud particles, in one lateral direction from the direct-transmission axis.

Abstract: The invention contemplates apparatus for simultaneous photometric observation of a plurality of elements in a liquid sample, wherein a dilute solution of the sample is atomized and fed to an elongate steady flame and wherein light from a hollow-cathode lamp, and containing at least one narrow-band emission line of one of the elements to be determined, is directed through the flame; plural photoelectric receivers, each with an associated filter unique to a line characteristic of a different specific element to be determined, are disposed to respond to light passing through the flame or to light emitted by the flame, as the case may be. The detected outputs of the receivers are fed to a computer for evaluation, the outputs of emission receivers being first electronically processed for the effective removal of "dust flashes" in the flame.