He was born in
Edinburgh in 1707, the son of Rev James Webster, second charge of Tolbooth parish in
St Giles Cathedral and a covenanting minister, originally from
Fife. Alexander was educated at the High School of Edinburgh then studied at
Edinburgh University. He was licensed to preach by the Presbytery of
Haddington in March 1733. In September 1733 Alexander was ordained as minister of the Church of Scotland at
Culross Parish Church in western
Fife. On 2 June 1737 he was translated to Tolbooth parish, one of the four parishes contained in
St Giles Cathedral in
Edinburgh. He propounded a scheme in 1742 for providing pensions for the widows of ministers. The tables which he drew up from information obtained from all the presbyteries of Scotland were based on a system of
actuarial calculation that supplied a precedent followed by insurance companies in modern times for reckoning averages of longevity. Webster published in 1748 his
Calculations, setting forth the principles on which his scheme for widows' pensions was based; he also wrote a defence of the
Methodist movement in 1742, and
Zeal for the Civil and Religious Interests of Mankind Commended (1754). In 1753, he was elected
Moderator of the General Assembly of the Church of Scotland. In 1771, he was appointed a Dean of the
Chapel Royal and
Chaplain in Ordinary to
George III in Scotland. Socially, despite his 'High Flying' Evangelical position in the Kirk, he was a convivial man, known as
Bonum Magnum for his capacity for claret. His wife's nephew Boswell often mentions dining with the family. He died in Edinburgh on 25 January 1784 and is buried beside Mary in
Greyfriars Kirkyard, Edinburgh, in a now-unmarked grave. ==Family==