This section is from the book "The Engineer's And Mechanic's Encyclopaedia", by Luke Hebert. Also available from Amazon: Engineer's And Mechanic's Encyclopaedia.
Quadrant in Geometry, the quarter or fourth part of a circle, and therefore containing an angle of 90 degrees.
Quadrant also denotes a mathematical and optical instrument, of great use in navigation and astronomy, for taking the altitude of the sun and stars.
 
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