Mathematician, astronomer, and horologist.

Worked as a shepherd and domestic servant (1720-34), portrait painter, and scientific lecturer (from c. 1748). Published numerous scientific works, including two popular astronomy texts, Astronomy Explained on Sir Isaac Newton’s Principles (1756) and The Young Gentleman’s and Lady’s Astronomy (1768). Built several orreries and other devices to illustrate physical and astronomical principles. Improved on Franklin’s design for a clock (1758). Fellow of the Royal Society (1763). Published some of Franklin’s magic squares and his magic circle (1767). Technological consultant to George III (from 1768).

Son of John and Elspet (Lobban) Ferguson of Banffshire. Married Isabella Wilson (1739); four children.