Smith, Hamilton Lanphere, 1819-1903. [from old catalog] · Cleveland, M. C. Younglove and company · leaf 85
o Greenwich time,and give, at any moment, by simple inspection, the precise timewhich is then indicated by the clock at Greenwich. On a clearday, the true time on ship-board, or the exact instant of apparentnoon, is ascertained by means of the quadrant, figured below.This is an arc of a circle,… … A is called the index glass; it is a plane quicksilvered glassreflector, placed, by means of adjusting screws, truly perpendicularto the plane of the quadrant, and attached to the brass index armA B, this index turns on a pin directly under A. C is called the QlADRA>I. 83 horizon glass, and is…
Astronomy · Meteorology · Geology · Paleontology
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