368: A RARE 18TH C. BRASS MOUNTAIN ALIDADE SURVEY INSTRUMENT

The rare, early brass surveyor's instrument, probably French, with straight edge having two finely shaped vanes at either end, one straight vane with string slot and one crescent shape vane opposite, making it a very effective instrument for surveying steep slopes when used with a plane table. This is an interesting example with decorative design elements, nice quality and very good patina.
Measures 20 x 6.5 inches.
Very good condition throughout, no damage, repair or heavy wear.
Provenance: The estate of a collector active in Historical Re-enactment, Surveying the Frontier, Scientific Instruments. Lewis and Clark.
$1,000 - $1,500