(1824-1884), Scientific instrument maker

James White was baptized on 23 November 1824 in the parish of Kildalton in Islay, Argyll. White was apprenticed about 1839 to Gardner & Co., mathematical, optical, and philosophical instrument makers. He probably worked for the firm as a journeyman until he was about twenty-five, when he set up on his own with £160, partly borrowed from friends, at 14 Renfield Street, Glasgow, in March 1850.

White received early encouragement from William Thomson, professor of natural philosophy at Glasgow University, for whose laboratory he supplied materials and experimental teaching apparatus from 1854 onwards. White helped to equip Thomson's pioneering new laboratory at Gilmorehill in 1870 and was appointed optician and philosophical instrument maker to the university.

White's earliest known partner was John Haddin Barr, with whom he traded as White and Barr from 1857 until the dissolution of their partnership in the autumn of 1859, apparently because of Barr's emigration to New Zealand. Within two years a deficit of over £1600 forced White to petition for sequestration, in August 1861. After satisfying his creditors by December 1861, he resumed business, and later entered into partnership with Robert McCracken, a dentist; this was dissolved in December 1876.

Thomson designed, and in 1858 patented, the mirror galvanometer for the Atlantic telegraph project, crediting White with the innovative substitution of lightweight silvered microscope glass for the usual metal mirror. Thomson's attachment to White as a maker was later attributed to the galvanometer's success in enabling the first transatlantic telegraphic contact. He was elected a member of the Glasgow Philosophical Society in 1876.

On 5 September 1877 White married Jane Reid, sister of David Hay Reid, muslin manufacturer. Before an expansion into larger workshops in 1883 White had taken as partners his assistants Mathew Edwards and David Reid (unrelated to his wife). They continued the firm after White's death at 20 Hamilton Drive, Glasgow, on 15 August 1884.