In the quantitative measurement of one of plural components contained in a specimen, three kinds of light wavelengths are used to eliminate the influence of two components except one to be measured. The outputs with respect to the three kinds of wavelengths are converted to the corresponding electric signals, which are in turn subjected to the logarithmic conversion. One output with respect to one of the three kinds of wavelengths is inverted in polarity and the polarity-inverted output is then combined with the other outputs so that the relationship between the light absorption quantity and the wavelength, concerning the component to be measured, can be obtained with the result that the quantity of the component in the specimen can be determined.

Color former is added to blood serum sample color it, and measurements for specific components are determined based on the light absorbance caused by coloring. For one sample, a differential light absorbance between two wavelengths at each of long wavelength region, middle wavelength region and short wavelength region within a visible wavelength band is determined. The degree of chyle is determined from the measurements for the long wavelength region, the degree of hemolysis is determined from the measurements for the middle wavelength region, and the degree of icterus is determined from the measurements for the short wavelength region. The measurements for the specific components are then corrected by the degree of chyle, degree of hemolysis and degree of icterus to obtain highly correct measurements.

A multichannel spectrophotometer has a single radiant energy source formed into a multiplicity of radiant energy beams which are each simultaneously intercepted by segments of a rotary source filter wheel, the spectral radiant energy output selected by each filter segment being directed into a separate source radiant energy conduit and transmitted to a remote sample station where a cuvette containing a sample to be analyzed is located, the radiant energy outputs of each cuvette being directed into a separate detector radiant energy conduit where each conduit is intercepted by a filter segment of a second rotating detector filter wheel identical to the source filter wheel and rotated in aligned synchronism therewith, the spectral radiant energy outputs of each segment of the detector filter wheel being further directed into a separate radiant energy detector and signal processing electronics associated with that sample station or spectrophotometer channel from which the radiant energy signal being detected and analyzed has been received. Central control, timing and display electronics are shared by each channel and may be overall programmed and controlled by computer. In one application involving the measurement of fluorescence, the filters of the detector filter wheel will be different from the filters of the source filter wheel so as to excite the sample cuvette at one wavelength and to measure fluorescent response at another.

Process and device for detecting impurities in the atmosphere by an inteny-time rate technique whereby chemiluminescent reaction curves are developed and found to be representative of specific materials. Hence, by comparing known intensity-time rate curves with curves had by actual measurings, the invention enables the user to discern many more materials never before detected.

A combustion technique and control is provided by the use of an optical pyrometer by means of which combustion control is afforded in accordance with the inspection of the combustion flame. The preferred optical pyrometer takes the form of an optical pyrometer having a single measurement cell which is alternately exposed to the flame through different filters arranged on a rotating disc driven by a motor. The circuit associated with the optical pyrometer, for purposes of generating control signals, features the use of a synchronous D. C. restorer which establishes a reference level for minimum signal distortion. Also employed is an AGC circuit by means of which one of the signals derived from one of the aforementioned filters is utilized to minimize undesired variations in the results. Gating logic is used to separate the two channels derived from the different filters and actually demultiplexes the two separate channels. It also recognizes a small, synchronous pulse derived from a sync opening on a disc on which the filters are mounted. Low pass filtering and D. C. amplification is employed to provide for filtering of noise and spurious signals and to compensate for duty cycle loss.