Accession No
3728
Brief Description
compass or clinometer, by Canivet, French, 1770
Origin
France; Paris
Maker
Canivet
Class
magnetism; surveying
Earliest Date
1770
Latest Date
1770
Inscription Date
1770
Material
metal (brass, silver, steel); wood; hide (leather); cloth; glass
Dimensions
box length 112mm; breadth 119mm; height 31mm
Special Collection
Provenance
Purchased from Anthony Turner, 1989.
Inscription
‘Canivet a La Sphere
a Paris 1770.’ (on the corner of the base plate)
Description Notes
compass / clinometer, by Canivet, 1770.
Glazed brass compass / clinometer with silvered compass dial and locking device for compass needle. (Scale divided 0-360 by 10 to 1˚. Compass rose, fleur-de-lis North). Comes in lined wooden box covered in leather; signed by Canivet.
Condition: good (box: fair/poor); complete.
References
Events
Description
Magnetic compass
The magnetic compass consists of a magnetic needle attached to a compass card, graduated into angular points, and is used for navigation. The first known dry pivoted compass is dated as early as 1269.
The compass indicates the direction of the magnetic pole but there are problems caused by the difference between magnetic and true north (true north being the useful reading). The variation between the two must be calculated in order to obtain an accurate reading. True north was sometimes simply offset from the direction of magnetic north, but this did not allow for geographical variation. For this, charts were needed. The iron used in building ships during 19th century also led to problems because the magnetism of iron affected the compasses on board.
18/10/2002
Created by: Saffron Clackson on 18/10/2002
FM:43496
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