The book of sun-dials; originally compiled by the late Mrs. Alfred Gatty; now enl. and re-edited by H. K. F. Eden and Eleanor Lloyd (1900)
Gatty, Alfred, Mrs., 1809-1873, Eden, Horatia K. F. Gatty, Lloyd, Eleanor, Evans, Lewis · London, G. Bell · leaf 534
rpendicular to R D. Make C Y equal to S R, and join A Y. Then will A Y be the position of the substile. Through Y draw the long line G Y P M perpendicular to A Y. Make Y G equal to C R, and join A G. CONSTRUCTION OF SUN-DIALS 495 Then will the angle Y A G be the angle of the gnomon.From Y draw Y^… … Draw O P 12, cutting the equinoctial circle in 12. PVom 12 lay off arcs of 15 degrees each, as at i, 2, 3, etc., and 11, 10, 9, etc. From o draw lines 01,02, etc., and 011,0 10, etc., cutting the line G Y P Min I. II., etc., and XI., X., etc. Then the true hour lines will be drawn from A to I., II…
Sundials
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