Jesse Ramsden, English Instrument Maker

- Image ID: HRKPEA
Jesse Ramsden, English Instrument Maker
Science History Images / Alamy Stock Photo
Image ID: HRKPEA
Jesse Ramsden (October 6, 1735 - November 5, 1800) was an English mathematician, astronomical and scientific instrument maker. In 1758 he was apprenticed to a mathematical instrument maker and he proved so proficient that he was able to set up his own business only four years later. The quality and accuracy of his instruments established his reputation as the most able instrument maker in Europe for the next forty years until his death in 1800. He created one of the first high-quality dividing engines. This led to his speciality in dividing circles, which began to supersede the quadrants in observatories towards the end of the 18th century. In 1768, he constructed a widely used version of a plate electrical generator. He published a Description of an Engine for dividing Mathematical Instruments in 1777. Ramsden was the first to carry out in practice a method of reading off angles by measuring the distance of the index from the nearest division line by means of a micrometer screw which moves one or two fine threads placed in the focus of a microscope. He died in 1800 at the age of 65.