prismatic compass

noun

1. a hand compass equipped with sights and prisms to permit aiming the instrument at a point and at the same time reading the compass direction of the point.

Word History and Origins

Origin of prismatic compass¹

First recorded in 1850–55

Example Sentences

Mr. Downing and myself worked independently in getting as thorough knowledge of the river as possible, he taking the courses with a prismatic compass, and estimating distances by the eye, and sketching in the topographical features of the surrounding country, while I estimated also the distances to marked points, and paid particular attention to the bed of the river, sounding wherever there were any indications of shallowness.

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The top of the easy passage bears by prismatic compass 23� from the highest cairn, and is marked by a large stone.

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He got out his very best prismatic compass, which he valued more than any of his other possessions, as it was virtually impossible to replace it, sighted carefully, determined the direction of the attack, ordered the advance, put the compass on the ground, and walked off, leaving it there.

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If we work out the exact degree by the map of the 'blow,' I can obtain the right direction by prismatic compass, and a few minutes before 'time' lift the camera up and cover the spot direct.

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“This, at any rate, will be proof against bad luck,” she said, as she undid the case, and drew out a prismatic compass.

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