Balfour Stewart (1.11.1828-19.12.1887) was a Scottish physicist and a Fellow of the Royal Society (1862). He was born in Edinburgh. He graduated from the universities of St Andrews and Edinburgh. In 1856 —58 he was an assistant at the University of Edinburgh, in 1859 — 71 director of the Kew Observatory, and in 1870 — 87 professor at the University of Manchester.
His work was in the fields of spectral analysis, thermal radiation and meteorology. He studied the relation between the emission and absorption of thermal radiation by bodies. He established experimentally (1858) that the absorptive power of a body is equal to its emissive power (for any kind of thermal rays).
The B. Rumford Medal (1868).