George Graham, clock and instrument maker, c 1740s.
© Science Museum / Science & Society Picture Library
Oil on canvas painting by Thomas Hudson (1701-1779), showing Graham (1673-1751) seated beside a mercury compensating pendulum in an open clock case, c 1710. Following his apprenticeship with London clockmaker Henry Askem, Graham, the inventor of the mercurial pendulum, was considered one of the greatest instrument makers of his day. He made various astronomical instruments, and contributed significantly to the advancement of precision timekeeping.