Benjamin Martin, English mathematician and instrument maker, c 1730s.

Engraving. Benjamin Martin (1704-1782) was a schoolmaster and travelling lecturer who invented several optical instruments. These included the first 'universal microscope', a portable microscope, in 1738, and the 'pocket reflecting microscope', later called the 'drum microscope', which remained popular well into the 19th century. He also published a number of texts, including 'Philosophical Grammar' (1735) and 'An English Dictionary' (1749), and his own magazine, 'Martin's Magazine' (1755-1764).