Henry Gregory (1744–1782) was an English

mathematical Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...

and optical instrument maker. Gregory was apprenticed to John Fowler in 1732 and was himself in business from c. 1750–1792 from premises in Francis Court, Clerkenwell,

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

and an establishment known as "The Azimuth Compass" in Leadenhall Street, London. His company later became known as Gregory and Son. Gregory manufactured navigational instruments, including

quadrants Quadrant may refer to: Companies * Quadrant Cycle Company, 1899 manufacturers in Britain of the Quadrant motorcar * Quadrant (motorcycles), one of the earliest British motorcycle manufacturers, established in Birmingham in 1901 * Quadrant Privat ...

of the type invented by

John Hadley John Hadley (16 April 1682 – 14 February 1744) was an English mathematician, and laid claim to the invention of the octant, two years after Thomas Godfrey claimed the same. Biography He was born in Bloomsbury, London the eldest son of ...

and

compass A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself wit ...

es. One of his

azimuth compass An azimuth compass (or azimuthal compass) is a nautical instrument used to measure the magnetic azimuth, the angle of the arc on the horizon between the direction of the sun or some other celestial object and the magnetic north. This can be compare ...

es traveled with the explorer James Cook on his second voyage to the southern

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...

in 1772–1775. An azimuth compass is a compass fitted with vertical sights, used to take the magnetic azimuth of a star or planet. Surviving examples of the azimuth compass exist in the collections of the

National Maritime Museum The National Maritime Museum (NMM) is a maritime museum in Greenwich, London. It is part of Royal Museums Greenwich, a network of museums in the Maritime Greenwich World Heritage Site. Like other publicly funded national museums in the Unite ...

, Greenwich and the Smithsonian National Museum of American History.

References

* 1744 births English inventors 1782 deaths British scientific instrument makers Engineers from London {{UK-engineer-stub