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History of Sundials

Why the Sun Dial keeps time

Developing and Making Sundials

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Sundial Hour Lines Lay out

Sundial "Furniture"

Declination Lines of Sundials

Portable Sundials

Interesting Sundials of the World

LAYING OUT THE SUNDIAL HOUR LINES - Page 16

Setting the Sundial In setting the sundial, it is essential that the plane upon which it is to be placed is vertical. The declination of the plane having been carefully determined, attach the sundial securely. Declining Sundials in General In the foregoing example, the construction of the hour lines for a south sundial declining 28°W, in latitude 4o°3o'N, has been shown in detail. These lines will also serve for a south sundial declining east, or a north sundial declining west, and a north sundial declining east, provided each sundial has the same declination and latitude. This will be easily seen if the hour lines have been drawn on transparent paper. The hour lines for a south sundial declining east 28° will be seen; if the figure is turned upside down, the hour, lines will be those for a north sundial declining west 2-8"; and the reverse side of the figure, when turned upside down, will show the hour lines for a north sundial declining east 28°. It must be remembered that the morning hours of a sundial declining west will become the afternoon hours of a sundial declining east; and that the substyle of a sundial declining west will fall among the afternoon hours. But the substyle of a sundial declining east will fall among the morning hours. Therefore, while making one sundial, the hour lines for all four declining sundials have been constructed. THE RECLINING SUNDIALS PLATE VIII There are four types of reclining sundials: the direct south, north, east, and west sundials. These may be subdivided into two groups the north-south and east-west.

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