Paper, 'On a thermopile and galvanometer combined' by George Forbes Forbes writes: 'The author has lately made use of a special form of thermopile and galvanometer combined, which is very sensitive for the measurement of radiation. The apparatus is especially suitable for use as a line-thermopile. The first experiments were made with two half tubes, one of antimony the other of bismuth, soldered together so as to make a short tube about 2 cm. external diameter, the walls being 2 mm. thick, and the length of tube about 2 or 2½ cm.' Annotations in pencil and ink. Subject: Electricity / Scientific apparatus and instruments / Engineering Received 4 February 1886. Read 18 February 1886. Communicated by Lord Rayleigh [John William Strutt]. A version of this paper was published in volume 40 of the Proceedings of the Royal Society as 'On a thermopile and galvanometer combined'. 1886