Instruments and methods used in radiometry

Instruments and methods used in radiometry

Year: 1908

This paper deals with (our instruments for measuring radiant energy, viz,, the radio-micrometer, the linear thermopile, the radiometer, and the bolometer, with its auxiliary galvanometer. The radio-micrometer is capable of great improvement, by reducing its weight, by lengthening its period, and by placing it in a vacuum. On account of para- and dia-magnetism the sensitiveness of the radio-micrometer is very limited, being perhaps only a fifth of that of the best bolometers described. The Rubens thermopile was found to be as sensitive as the best bolometer, and its heat capacity can be greatly reduced by using thinner wires (of 0.06 to 0.08 mm. diam.), which can be made shorter, thus keep