Watt, John, (1694-1737), land surveyor and teacher of mathematics and navigation

John Watt senior was the son of Thomas Watt, the older brother of James Watt of Greenock, and the uncle of James Watt, the engineer and inventor. He appears to have followed his father's profession and by 1715, he had become a teacher of mathematics and navigation. He also taught book-keeping. He moved to Glasgow in 1719. A considerable part of his work seems to have been as a land surveyor and numerous surveys and calculations have survived among his papers. His best-known survey was one of the Firth of Clyde, made about 1734, and published, with additions and alterations, by his brother and nephews in 1759-60. He also, like his brother, had interests in various shipping concerns.

John Watt senior married twice, but both wives died and no children survived. In 1728 he married Janet Todd. Their son John was born and died in May 1729 and Janet died in 1731. Her father, John Todd, was a merchant in Glasgow who seems to have dealt in tobacco and textiles. His second marriage was to Christian Tennent, in 1734. She was the daughter of Hugh Tennent, a merchant of Glasgow. They had a daughter Margret, born in 1735, but both mother and child died soon afterwards.