Monday, 7 November 2011
A small sundial made from a cartwheel rim and two similar sized barrel rings.
When making these devices, you need to know where they are to be used, as the angle of the gnomon (through the middle) when facing true north depends on the latitude, and the calibration of the chapter ring depends on the longitude. Naturally, when the clocks change for summer it too has an effect, so probably best to keep your watch after all...
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