Stránka:book 1912.djvu/248

2l6 The Book of Woodcraft A HOME-MADE COMPASS If you happen to have a magnet, it is easy to make a compass. Rub a fine needle on the magnet; then on the side of your nose. Then lay it gently on the surface of a cup full of v/ater. The needle will float and point north. The cup must not be of metal. AN INDIAN CLOCK, SHADOW CLOCK OR SUNDIAL To make an Indian shadow clock or sundial, prepare a smooth board about fifteen inches across, with a circle divided by twenty-four rays into equal parts. Place it on a level, solid post or stump in the open. At night set the dial so that the twelve o'clock line points ex- actly north, as deter- mined by the Pole Star and nail it down. Then, fix a stick or pointer with its upper edge on the centre and set it exactly pointing to the Pole Star (a b) ; that is, the same angle as the latitude of the place, and fix it there imimiov- ably; it may be necessary to cut a notch (c) in the board to permit of a sight line. The hours eight at night to four next morning may as well be painted black. As a time- piece, this shadow clock will be found roughly correct.