Accession No
6761
Brief Description
Kater magnetic compass, by Thomas Jones, English, 1820 (c)
Origin
England
Maker
Jones, Thomas
Class
magnetism; navigation; military
Earliest Date
1820
Latest Date
1820
Inscription Date
Material
wood; glass; metal (brass); paper; mineral (mica)
Dimensions
case length 158mm, width 155mm, height 50mm; compass diameter 130mm, length 167mm, height 25mm (erected) 155mm
Special Collection
Provenance
Purchased from Tesseract, USA.
Inscription
(Trade label)
"By Special Appointment, Thomas Jones (Pupil of Ramsden), Astronomical and Philosophical Instrument Maker To His Royal Highness The Duke of Clarence, 62 Charing Cross, London"
Description Notes
Kater magnetic compass, English, 1820 (c).
The wooden case can be fastened with two hooks on both sides. There is a key hole but the key is not present. There is a paper trade label with the name of the maker and the retailer, "By Special Appointment, Thomas Jones (Pupil of Ramsden), Astronomical and Philosophical Instrument Maker To His Royal Highness The Duke of Clarence, 62 Charing Cross, London." The compass is rather large, measuring 13cm diameter, with a floating compass ring and an external arrestor. A green paper ring is supported on the needle ends by two circular arcs of cut mica sheet. There is a folding sight vane that can be erected, and across the compass a mounted sighting box.
References
Events
Description
A Kater magnetic compass is a prismatic compass with a magnetic needle. It was first invented by Captain Henry Kater (1777–1835) who was surveying with the British army in India. The prismatic compass was patented by Schmalcalder one year later.
Henry Kater, FRS, FRAS, was trained in law but later became a physicist. During his military career, he assisted with the Great Trigonometric Survey. Later he published multiple works regarding metrology (the study of measurement) and astronomy. The prismatic compass which he invented was used in the next 50+ years, and his Bakerian Lecture (an award for outstanding contribution in science, granted by the Royal Society) "On the best kind of Steel, and form, for a Compass Needle" was much praised.
11/10/2022
Created by: Guey-Mei Hsu on 11/10/2022
FM:47557
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