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Abney Level for Rapid Calculation of Object Height. This surveying instrument is the Mark 5 military issue # B7332 and was made for the British army by WRP, circa 1940. This solid brass Abney Level consists of a telescope and an adjustable tubular spirit level, which is connected to a semicircular scale and vernier marked in both slope and degrees (±90°). Aluminum rotating drum gear is used for fine adjustment of the bubble with 13 degrees/turn and a magnifier assists in reading the vernier. This sophisticated friction gear mechanism can measure angles with accuracy of 10 seconds of an arc. Length 11 cm (4 ½ inches). |
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