American horological journal, devoted to practical horology (1869)
Miller, George B · New York, G. B. Miller · leaf 97
north edge of the board isplaced against an exact south wall, the lineN. S. becomes the 12 oclock line ; or what-ever the wall declines, that line is perpendicu-lar to the wall itself. To take the Declination.—In the forenoon,when the sun is shining, apply the edge ofthe instrument, A B, to the… … until afternoon, and observe when the top ofthe shadow is on the same circle, and theremake a dot at G. Take down the instrument,and with your compasses subdivide the arcF H at G, and draw a line through the cen-tre to K, and you will have the true 12oclock line. The angle N I G is the degreeof…
Clocks and watches
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