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Sundial Hour Lines Lay out

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Declination Lines of Sundials

Portable Sundials

Interesting Sundials of the World

PORTABLE SUN sundials - Page 4

The time is obtained by turning the top of the sundial until the gnomon lies over a vertical line on the face of the sundial corresponding to the date; then the sundial is turned until the shadow is parallel to the vertical lines, when the position of the end of the shadow records the time. The vertical lines are crossed by curved lines corresponding to the hours of the day. Sundials K and L are made of boxwood; M is a boxwood cylinder with a paper sundial plate. The small sundial in the upper right corner at N, is really a camouflaged standard time sundial of Japanese origin. The sundial face resembles that of a clock, the hour lines radiating from the center in snaky curves. A semicircular brass arch (invisible in the illustration) is mounted on the polar axis. A small disk bears the days of the year to which an adjust-able pointer may be set. When in use, the sundial plate actually faces the north, the brass arch faces the south. The pointer hand moves with the arch which is turned until the thin-nest shadow can be seen on the polar axis; then the time is read by the position of the pointer hand. The lines are snaky in appearance because the correction for standard time has been accounted for in the hour lines themselves. Isn't this sufficient to make you want to try your hand? If not, perhaps a few more specimens selected from the Ernst collection will hasten you on your way to making your own collection. A beautifully wrought horizontal sundial of brass, made by P. Lemaire of Paris. The base is fitted with four leveling screws and a compass. The sundial plate contains three hour circles, for use in different latitudes.

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