What instrument for measuring radiant heat was devised by Langley, an American physicist, in 1881?
Samuel Pierpont Langley over solid ground. Air and sea craft, facilities, a unit of solar radiation, and an award have been named in Langley's honor, including: In 1880 Langley invented the bolometer, an instrument initially used for measuring far infrared radiation. The bolometer has enabled scientists to detect a change of temperature of less than 1/100,000 of a degree Celsius. It laid the foundation for the measurements of the amount of solar energy on the Earth. His published an 1881 paper on it, "The Bolometer and Radiant Energy". He made one of the first attempts to measure the surface temperature of the Moon,
Potentiometer (measuring instrument) Potentiometer (measuring instrument) A potentiometer is an instrument for measuring voltage by comparison of an unknown voltage with a known reference voltage. If a sensitive indicating instrument is used, very little current is drawn from the source of the unknown voltage. Since the reference voltage can be produced from an accurately calibrated voltage divider, a potentiometer can provide high precision in measurement. The method was described by Johann Christian Poggendorff around 1841 and became a standard laboratory measuring technique. In this arrangement, a fraction of a known voltage from a resistive slide wire is compared with an unknown voltage by