Davies, Charles, 1798-1876 · New York, Cincinnati [etc.] American book company · leaf 397
ors perpendicularto the plane of the paper,—which is taken as the planeof reflection. A ray of light from A isreflected, first from the mir-ror 1 in the direction GO,then by the mirror fi alongOT. The angle betweenthe first and last directionof the ray after these tworeflections is ATO. Draw GN and… … Fig. 4. ♦ For a fiill description of this instrument, see Chauvenete Spherical and PracticalAetronomy, published by Lippiucott io 1863, APP. B.] THE SEXTANT. 17 ce angleangle A10 = 2i - 2i ;NKO = i - i;ATO = 2NK0. Q. E. D. II Suppose now that the glass His unsilvered on the upper half; then a rayof…
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