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 536
ig. 8.—Having now ascertained the vertical height of the shadow of P forevery day in the year, transfer them to the face of the dial, and write the datesopposite each line. From the table of the equation of time set off the number of minutes andseconds on the right or the left of the meridian line… … you will not only have the true mean time (subject only to the slight error forLeap year, which will average only about -^ minute), but you will have the day ofthe month as well. By the true mean time I mean the mean or clock time for the longitude ofthe place. If it is desired to show Greenwich…
Sundials
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