FASCINATING EARLY QUADRANT, English, mid-17th century. This very thin brass quadrant is 3-3/4″ (9.5 cm) in radius, hand engraved on one side, with practice engraving of several numerals and letters on the reverse. There is a circumferential quadrant scale divided every degree, for use in measuring the angular altitude of sun, moon, stars, mountains, buildings, etc., by sighting along the edge and reading against a little plumb line which would be suspended from the apex. Next is a calendrical
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