Ramsden, Jesse (1735-1800), was a British pioneer in the design of mathematical and optical instruments. His best-known work is an eyepiece for a microscope, called a Ramsden eyepiece. Some such eyepieces contain a wire grid for scale measuring. Ramsden also invented an instrument for measuring the expansion of metal bars and a mounting for astronomical telescopes. Ramsden was born on Oct. 6, 1735, near Halifax, West Yorkshire, England. He died on Nov. 5, 1800.
