.png)
Edward Nairne 10" Equinoctial Ring Dial
[Text discription below.]
.jpg)
.png)
50077
A Large & Rare Universal Equinoctial Ring Dial:
English ca. 1760. This substantial Universal Equinoctial Ring Dial is made entirely of brass, and a single steel screw in the suspension assembly. The dial is 10 inches in diameter, 6 mm thick, and weighs 1,192.4 g. It is signed on the bridge "Nairne London" in script. The outer meridian ring is engraved with a latitude scale full circle (0-90°; four times), indicating that the Dial was manufactured for use worldwide, in either hemisphere. Only the date and one’s latitude are needed to determine the apparent solar time. The latitude scale is further subdivided into 1° increments, all above a running wheat leaf border. The wheat leaf border indicating possible membership to the London Trade Guilds. The hinged equinoctial chapter ring is divided every 2 minutes of time full circle (0-12 hrs; twice) with numbered engravings of 20-40-60 between each hour (Roman numerals.) Every half hour is engraved with a diamond. The suspension assembly is engraved with a latitude cursor and two scales of deviation subdivided into 1° increments. The suspension assembly is fitted to a sliding ring on the circumference of the meridian ring to set the latitude.
The central bridge is fitted with a sliding pin-hole gnomon adjustable to the correct solar declination using a date scale on one face, and a zodiacal scale with ± 23.5° Æ scale on the other. The date scale has engravings for each month of the year which are further subdivided for every day of the year, i.e. Jan 1-31, Feb 1-28, etc. The vernal equinox is set to March 20th, indicating that the dial was made post 1752, the date the Gregorian calendar was adapted in GB.
The reverse of the dial is engraved with the 0-90° solar altitude scale (Numbered by 10° and subdivided to 0.5°.) on the meridian ring and repeated in reverse on the equinoctial ring. This was to be used with a removable, shadow-casting straw or pin in the meridian ring, to measure the solar altitude and zenith distance. The dial is used closed for this purpose, with the suspension bracket set to 0° and the pin inserted in a hole corresponding to 45 degrees on the latitude scale. Condition: The dial is in very fine original condition throughout. Excellent and well cared for overall. Historical:
"Nairne London" refers to Edward Nairne (b 1726, w 1749, d 1806), a highly regarded mathematical instrument maker working in 18th century London (2). He collaborated with and made instruments for contemporaries such as Benjamin Franklin and Joseph Priestly (The discoverer of oxygen.). Edward Nairne was apprenticed to Matthew Loft (1741/2) and completed his apprenticeship in 1748 to become free of the Spectaclemaker’s Guild. He had 11 apprentices of his own, including Jesse Ramsden, producing a full range of scientific instruments. He made improvements to the Cuff Microscope, building it into a portable case and calling it a chest microscope. Examples of his instruments, that have survived, can be found in major museum collections. A reflecting telescope by him can be found in the National Maritime Museum in Greenwich (Inventory #AST0943). A refracting telescope (Inventory #70584) and a chest microscope (Inventory #37949) can be found at the Museum of The History of Science in Oxford. A reflecting telescope once owned by Samuel Williams (b 1743, d 1817), a Professor of Astronomy at Harvard (1780-1788) and made by Edward Nairne, is now in the Smithsonian. (The telescope was used by Professor Williams to observe the transit of Venus across the Sun in 1769 while in Bradford, Massachusetts.). In 1774, Edward Nairne formed a partnership with one of his apprentices, Thomas Blunt, and instruments produced by this pair bare the name Nairne & Blunt. The partnership lasted until 1793. Hence, instruments signed “Narine” can be dated pre-1774, i.e. 1749-1774. In 1776, he was elected a fellow of the Royal Society. Bibliography:
1. Museum of the History of Science: [Collectionsonline.hmsi.ac.uk]. 2. Clifton, Gloria (1995). Directory of British Scientific Instrument Makers 1550-1851, IBSN [0 302 00634 6] p. 196. 3. History database at the Adler Planetarium: [historydb.adlerplanitarium.org]. 4. Trade card of Edward Nairne: [tradecardsonline.nmsi.ac.uk].
5. The Gregorian Calendar, was introduced by Pope Gregory XIII in Feb 1582, but was not adapted in Great Britain until Sep 1752. This shifted the vernal equinox to Mar 21.
6. Picture of Edward Nairne: [www.en.wikipedia.org/wiki/Edward_Nairne].
7. Original Works: Nairne’s papers published in the Philosophical Transactions of the Royal Society include “Description of a New Constructed Equatorial Telescope” Vol 61 (1771), p. 223–225; “Water From Sea Ice” Vol 66 (1776), p. 249–256; “Experiments With the Air-pump,” Vol 67 (1777), p. 614–648; and “Experiments on Electricity,” Vol 68 (1778), p. 823–860. Other works are: Description of a Pocket Microscope (n.p., 1771); Directions for Using the Electrical Machine as Made and Sold by E. Nairne (London, 1773); Directions for the Use of the Octant (n.d.). 8. Some of Nairne’s instruments survive and may be seen in the collections of the Adler Planetarium, Chicago; Conservatoire National des Arts et Métiers, Paris; Harvard University, USA; the Museums of the History of Science at Oxford and Florence; The National Maritime Museum, Greenwich; The Naval Museum, Madrid; The Science Museum, London; and The Smithsonian Institution, Washington.
English ca. 1760. This substantial Universal Equinoctial Ring Dial is made entirely of brass, and a single steel screw in the suspension assembly. The dial is 10 inches in diameter, 6 mm thick, and weighs 1,192.4 g. It is signed on the bridge "Nairne London" in script. The outer meridian ring is engraved with a latitude scale full circle (0-90°; four times), indicating that the Dial was manufactured for use worldwide, in either hemisphere. Only the date and one’s latitude are needed to determine the apparent solar time. The latitude scale is further subdivided into 1° increments, all above a running wheat leaf border. The wheat leaf border indicating possible membership to the London Trade Guilds. The hinged equinoctial chapter ring is divided every 2 minutes of time full circle (0-12 hrs; twice) with numbered engravings of 20-40-60 between each hour (Roman numerals.) Every half hour is engraved with a diamond. The suspension assembly is engraved with a latitude cursor and two scales of deviation subdivided into 1° increments. The suspension assembly is fitted to a sliding ring on the circumference of the meridian ring to set the latitude.
The central bridge is fitted with a sliding pin-hole gnomon adjustable to the correct solar declination using a date scale on one face, and a zodiacal scale with ± 23.5° Æ scale on the other. The date scale has engravings for each month of the year which are further subdivided for every day of the year, i.e. Jan 1-31, Feb 1-28, etc. The vernal equinox is set to March 20th, indicating that the dial was made post 1752, the date the Gregorian calendar was adapted in GB.
The reverse of the dial is engraved with the 0-90° solar altitude scale (Numbered by 10° and subdivided to 0.5°.) on the meridian ring and repeated in reverse on the equinoctial ring. This was to be used with a removable, shadow-casting straw or pin in the meridian ring, to measure the solar altitude and zenith distance. The dial is used closed for this purpose, with the suspension bracket set to 0° and the pin inserted in a hole corresponding to 45 degrees on the latitude scale. Condition: The dial is in very fine original condition throughout. Excellent and well cared for overall. Historical:
"Nairne London" refers to Edward Nairne (b 1726, w 1749, d 1806), a highly regarded mathematical instrument maker working in 18th century London (2). He collaborated with and made instruments for contemporaries such as Benjamin Franklin and Joseph Priestly (The discoverer of oxygen.). Edward Nairne was apprenticed to Matthew Loft (1741/2) and completed his apprenticeship in 1748 to become free of the Spectaclemaker’s Guild. He had 11 apprentices of his own, including Jesse Ramsden, producing a full range of scientific instruments. He made improvements to the Cuff Microscope, building it into a portable case and calling it a chest microscope. Examples of his instruments, that have survived, can be found in major museum collections. A reflecting telescope by him can be found in the National Maritime Museum in Greenwich (Inventory #AST0943). A refracting telescope (Inventory #70584) and a chest microscope (Inventory #37949) can be found at the Museum of The History of Science in Oxford. A reflecting telescope once owned by Samuel Williams (b 1743, d 1817), a Professor of Astronomy at Harvard (1780-1788) and made by Edward Nairne, is now in the Smithsonian. (The telescope was used by Professor Williams to observe the transit of Venus across the Sun in 1769 while in Bradford, Massachusetts.). In 1774, Edward Nairne formed a partnership with one of his apprentices, Thomas Blunt, and instruments produced by this pair bare the name Nairne & Blunt. The partnership lasted until 1793. Hence, instruments signed “Narine” can be dated pre-1774, i.e. 1749-1774. In 1776, he was elected a fellow of the Royal Society. Bibliography:
1. Museum of the History of Science: [Collectionsonline.hmsi.ac.uk]. 2. Clifton, Gloria (1995). Directory of British Scientific Instrument Makers 1550-1851, IBSN [0 302 00634 6] p. 196. 3. History database at the Adler Planetarium: [historydb.adlerplanitarium.org]. 4. Trade card of Edward Nairne: [tradecardsonline.nmsi.ac.uk].
5. The Gregorian Calendar, was introduced by Pope Gregory XIII in Feb 1582, but was not adapted in Great Britain until Sep 1752. This shifted the vernal equinox to Mar 21.
6. Picture of Edward Nairne: [www.en.wikipedia.org/wiki/Edward_Nairne].
7. Original Works: Nairne’s papers published in the Philosophical Transactions of the Royal Society include “Description of a New Constructed Equatorial Telescope” Vol 61 (1771), p. 223–225; “Water From Sea Ice” Vol 66 (1776), p. 249–256; “Experiments With the Air-pump,” Vol 67 (1777), p. 614–648; and “Experiments on Electricity,” Vol 68 (1778), p. 823–860. Other works are: Description of a Pocket Microscope (n.p., 1771); Directions for Using the Electrical Machine as Made and Sold by E. Nairne (London, 1773); Directions for the Use of the Octant (n.d.). 8. Some of Nairne’s instruments survive and may be seen in the collections of the Adler Planetarium, Chicago; Conservatoire National des Arts et Métiers, Paris; Harvard University, USA; the Museums of the History of Science at Oxford and Florence; The National Maritime Museum, Greenwich; The Naval Museum, Madrid; The Science Museum, London; and The Smithsonian Institution, Washington.
.png)