Inventory no. 52661 - Former Display Label
FOLDING-RULE and CALIPERS of unknown origin
18th century
Brass and steel. Unsigned and undated.
One side of the rule is engraved with a linear scale of twelve main divisions occupying the full length of the rule, of which ten numbered divisions equal 247.1 mm.; two of the divisions are divided by diagonals. The other side of the rule has a short linear scale of ten divisions (=105 mm.), and another ? proportional scale, numbered from 1/2 to 48. There are two polished steel caliper points mounted on brass sliders with locking-screws, which can be moved along the rule when closed, and can be used in conjunction with the scales engraved on the rule. The brass-sliders are ornamented with devices worked à jour on each side of each slider, viz. a cannon; a ten-pointed 'star' within which is the letter, 'S'; two hearts pierced by an arrow, supported by four letters, 'S'; and a pentagon within a circle.
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Billmeir Collection