Abstract: A coaxial resonator comprises a housing with walls which are metallically conductive at least on the inner side, with an injection and tapping opening and with a tube rejecting from a wall of the housing into its inner space, being metallically conductive and being conductively connected with said wall. The tube ends at a distance from the inner surface of the opposite wall and comprises a metallic tuning body which is axially displaceable. The risk that intermodulation products are produced which are caused by abraded parts produced during the displacement of the tuning body is prevented in such a way that the tuning body is held coaxially in the tube by way of a rod made of dielectric material, without contacting the tube conductively, and that the end of the rod averted from the tuning body is configured for displacing the tuning body.

Abstract: A photometric method and photoelectric photometer for the quantitative determination of a substance or material in an analysis substance, wherein the course of the calibration curve representing the functional dependency of an optical measurement magnitude upon the concentration of the substance can be at least approximately determined by at most a number of few parameters. For a calibration curve parameter there is provided a reference sample which contains the substance to be analyzed in a known or unknown concentration.