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Date: |
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Description: | 71/4 No15 B4/Card s/1839 2910/apl.151844/28-0 July2.1846 Barrow 1846
No15 S
Card-Mica covered with paper, white with black and white markings, graduated to 1/4 points. At centre of card is a hole 2" diameter to accommodate pivot gimbal.
Needle- four heavy edge bar needles of rolled and hammered steel. the two central needles 6.75" long, each of two laminations, 0.5" deep at ends, each having an auxiliary needle, semi-circular in shape, attached to the centre. The two outer needles are 4" long and 0.5" deep and have two laminations each mounted 2" apart and attached to a light metal ring which is screwed to the card.
Pivot- Inverted type mounted in double gimbals dia. 1.75", attached to the two central needles by brass brackets. The pivot pin is adjustable vertically by being threaded.
Experimental dry compass card
caption: Record Shot - Do not reproduce. | Publisher: | "http://collections.rmg.co.uk/" | Rights holder: | "Royal Museums Greenwich" | Source: | Royal Museums Greenwich | Identifier: | http://collections.rmg.co.uk/collections... | Go to resource |
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