Jesse Ramsden (1735 – 1800), maker of the Ramsden theodolite.
School period
College/University
Career
Gallery of Jesse Ramsden
1766
Jesse Ramsden was one of the foremost instrument-makers of his age. Two Ramsden theodolites were used in the survey and the first could take a bearing on a mark 70 miles away with an error of only 1/180th of a degree. The theodolite shown here is the second instrument, which was still more accurate. Despite their great weight, the theodolites were carried to the tops of mountains, steeples and specially-built scaffolds to obtain lines of sight. The measurements taken during the survey were so accurate that they were used for the next 150 years.
Gallery of Jesse Ramsden
Jesse Ramsden, a scientific instrument maker.
Gallery of Jesse Ramsden
Jesse Ramsden. Mezzotint by J. Jones, 1790, after Robert Home. The original portrait by Home is in the Royal Society. This shows Ramsden with the dividing instrument before him.
Gallery of Jesse Ramsden
Jesse Ramsden (1735 – 1800).
Gallery of Jesse Ramsden
Jesse Ramsden (1735 – 1800).
Gallery of Jesse Ramsden
Jesse Ramsden (1735 – 1800).
Achievements
Jesse Ramsden made optical instruments like telescopes, theodolites, and sextants during the middle of the 18th century. One such instrument was a sextant much prized by Captain Cook in his voyages of discovery in the Great Southern Oceans.
Membership
Royal Society
1786 - 1800
Royal Society, London, England, United Kingdom
Ramsden was elected fellow of the Royal Society on 12 January 1786.
Awards
Copley Medal
1795
The Copley Medal of the Royal Society was bestowed upon Jesse Ramsden in 1795 for his "various inventions and improvements in philosophical instruments."
Jesse Ramsden was one of the foremost instrument-makers of his age. Two Ramsden theodolites were used in the survey and the first could take a bearing on a mark 70 miles away with an error of only 1/180th of a degree. The theodolite shown here is the second instrument, which was still more accurate. Despite their great weight, the theodolites were carried to the tops of mountains, steeples and specially-built scaffolds to obtain lines of sight. The measurements taken during the survey were so accurate that they were used for the next 150 years.
The Copley Medal of the Royal Society was bestowed upon Jesse Ramsden in 1795 for his "various inventions and improvements in philosophical instruments."
Jesse Ramsden. Mezzotint by J. Jones, 1790, after Robert Home. The original portrait by Home is in the Royal Society. This shows Ramsden with the dividing instrument before him.
This is the only mechanical planetarium ever manufactured by famous instrument maker Jesse Ramsden. It is incomplete, but the fact that its cover is missing allows us to admire its complex internal workings. Orrery, second half of 18th century. London, Science Museum, inv. 1936-645.
Jesse Ramsden made optical instruments like telescopes, theodolites, and sextants during the middle of the 18th century. One such instrument was a sextant much prized by Captain Cook in his voyages of discovery in the Great Southern Oceans.
(n 1768, Jesse Ramsden constructed a widely used version o...)
n 1768, Jesse Ramsden constructed a widely used version of a plate electrostatic generator. An electrostatic generator, or electrostatic machine, is an electromechanical generator that produces static electricity. By the end of the 18th Century, researchers had developed practical means of generating electricity by friction, but the development of electrostatic machines did not begin in earnest until the 18th century, when they became fundamental instruments in the studies about the new science of electricity. Electrostatic generators operate by using manual power to transform mechanical work into electric energy. Electrostatic generators develop electrostatic charges of opposite signs rendered to two conductors, using only electric forces, and work by using moving plates, drums, or belts to carry electric charge to a high potential electrode.
1768
machine to divide arcs of circles automatically
(The instrument has a mahogany frame with three legs and t...)
The instrument has a mahogany frame with three legs and three frictionless wheels. These wheels support a heavy bronze wheel which is covered on its outer rim with a brass ring, cut with 2160 gear teeth. These teeth engage a screw on one side of the machine. Turning this screw 6 times rotates the carriage for the stylus exactly one degree. An object to be divided was clamped to the arms of the bronze wheel, with the cutting mechanism was above it.
1775
five-foot vertical transit circle
(The 5-foot diameter Palermo circle manufactured by Jesse ...)
The 5-foot diameter Palermo circle manufactured by Jesse Ramsden to measure apparent positions of astronomical objects.
1777
theodolite
(A theodolite (Amer. "transit") is an instrument for measu...)
A theodolite (Amer. "transit") is an instrument for measuring both horizontal and vertical angles, as used in triangulation networks. It consists of a telescope mounted movably within two perpendicular axes, the horizontal or trunnion axis, and the vertical axis. These must be mutually perpendicular. The optical axis of the telescope, called sight axis and defined by the optical center of the objective and the center of the cross-hairs in its focal plane, must similarly be perpendicular to the horizontal axis. Both axes of a theodolite are equipped with graduated circles that can be read.
1785
Shuckburgh telescope
(The Shuckburgh telescope or Shuckburgh equatorial refract...)
The Shuckburgh telescope or Shuckburgh equatorial refracting telescope was a 4.1 inch diameter aperture telescope on an equatorial mount completed in 1791 for Sir George Shuckburgh (1751–1804) in Warwickshire, England, and built by British instrument maker Jesse Ramsden.
1791
sextant
(A sextant is a measuring instrument used to measure the a...)
A sextant is a measuring instrument used to measure the angle of elevation of a celestial object above the horizon. Making this measurement is known as sighting the object or taking a sight. The angle, and the time when it was measured, are used to calculate a position line on a nautical or aeronautical chart. A common use of the sextant is to sight the sun at noon to find one's latitude.
Jesse Ramsden was an English mathematician, optician, physicist, and astronomical instrument maker. He is known for constructing the dividing engine, Ramsden eyepiece, surveying instruments, and optical telescopes. Ramsden was one of the finest scientific instrument makers in Britain in the last half of the 18th century.
Background
Jesse Ramsden was born at Salterhebble near Halifax, Yorkshire, England on October 6, 1735. He was the son of a Halifax innkeeper and the great-nephew of Abraham Sharp, mathematician, instrument maker, and assistant to the Astronomer Royal, John Flamsteed.
Education
Having attended the free school at Halifax for three years, he was sent at the age of twelve to his uncle at Craven in the North Riding, and there studied mathematics under the Rev. Mr. Hall. After serving his apprenticeship with a cloth-worker in Halifax, he went in 1755 to London, where in 1758 he was apprenticed to a mathematical instrument maker.
Career
After four years’ study of mathematics, Ramsden was apprenticed at sixteen to a clothworker in Halifax. In 1755, upon finishing this service, he moved to London, where he worked as a clerk in a cloth warehouse. In 1758 he apprenticed himself to the mathematical instrument maker Burton. Ramsden opened his own shop in the Haymarket in 1762, moving to larger quarters at 199 Piccadilly in 1775.
His great skill brought him commissions from the foremost practitioners of the period, including J. Sisson, J. Adams, J. Dollond, and E. Nairne. In 1774 Ramsden published Description of a New Universal Equatorial Instrument, which improved on the design of Short’s portable telescope mounting. Ramsden's mounting was quickly accepted and served to enhance his growing reputation.
A passion for precision was the motivating force behind Ramsden’s development of the dividing engine, his greatest contribution to the technology of the era. His first machine, built around 1766, produced only moderate improvement in the accuracy he sought, but the machine constructed in 1775 reduced the error to less than one-half second of arc as compared to the three seconds of arc of the first machine. This achievement earned him a grant from the Commissioners of the Board of Longitude in 1777.
Ramsden’s shop grew until the staff numbered about sixty workmen. At no time, however, did he permit the quality of his output to diminish. By 1789 he had produced someone thousand sextants, as well as theodolites, micrometers, balances, barometers, and the many philosophical instruments required by the physicists of the period. It appears that the demand far exceeded his capacity for production. In 1784 William Roy, who was conducting the trigonometric survey that linked England with the Continent, ordered a three-foot-diameter theodolite from Ramsden, who took three years to complete it.
Ramsden also supplied many of the observatories of Europe with new achromatic telescopes equipped with accurately divided circles. The altazimuth instrument he built for Piazzi for the observatory at Palermo was equipped with a five-foot-diameter vertical circle. Its graduations were read by means of the micrometer microscope that Ramsden had developed. This instrument was completed in 1789, only a year late, probably because Piazzi personally expedited the project.
The Royal Society awarded him the Copley Medal (1795) for “various inventions and improvements in philosophical instruments.” Many of Ramsden's instruments have been preserved and may be seen at the Smithsonian Institution, the Science Museum and the National Maritime Museum in London, the Museum of the History of Science in Florence, Teyler’s Museum in Haarlem, the Conservatoire National des Arts et Metiers in Paris, and in many other museums. His portrait is in the Science Museum in London.
(The 5-foot diameter Palermo circle manufactured by Jesse ...)
1777
sextant
(A sextant is a measuring instrument used to measure the a...)
Ramsden Electrostatic Generator
(n 1768, Jesse Ramsden constructed a widely used version o...)
1768
machine to divide arcs of circles automatically
(The instrument has a mahogany frame with three legs and t...)
1775
Shuckburgh telescope
(The Shuckburgh telescope or Shuckburgh equatorial refract...)
1791
theodolite
(A theodolite (Amer. "transit") is an instrument for measu...)
1785
quadrant
Membership
Ramsden was elected fellow of the Royal Society on 12 January 1786, and in 1794 he was made a member of the Imperial Academy of St. Petersburg.
Royal Society
,
United Kingdom
1786 - 1800
Personality
Ramsden was famous for missing deadlines. He drove clients (like King George) to distraction. Small wonder that, when he died in 1800, Dollond family executors could recoup only a tiny fraction of all the money owed him.
Connections
Ramsden married Sarah Dollond, daughter of John Dollond the famous maker of high-quality lenses and optical instruments. Little is known of their life together but Sarah did not accompany him when he moved his workshop (and home). They had no children.