Stránka:roll 1917.djvu/350

3x8 Woodcraft Mantial for Boys the Little Bear or Little Dipper, the Big Dipper or Big Bear, Cassiopeia's Chair, Orion, the Bull, Orion's Hound, Orion's Little Dog, the Pleiades and the Hyades; the Lyre (later). The Moon The moon is one fourth the diameter of the earth, about one fiftieth of the bulk, and is about a quarter of a nuUion miles away. Its course, while very irregular, is nearly the same as the apparent course of the sun. It is a cold, solid body, without any known atmosphere, and shines by reflected simlight. The moon goes around the earth in twenty-seven and a quarter days. It loses about fifty-one minutes in twenty-four hours; therefore it rises that much later each successive night on the average, but there are wide deviations from this average, as, for example, the time of the Harvest and Himter's moons in the fall, when the full moon rises at nearly the same time for several nights in succession. According to most authorities, the moon is a piece of the earth that broke away some time ago; and it has followed its mother around ever since. The hole it left in its place is supposed to be the North Pacific Ocean. The Stars as Tests of Eyesight In the sky are several tests of eyesight which have been there for some time and are likely to be. The first is the. old test of Mizar and Alcor. Mizar, di^ Horse, is the star at the bend of the handle of the Dipper. Just above it is a very small star that astronomers call Alcor, or the rider. The Indians call these two the "Old Squaw and the Pappoose on Her Back." In the old world, from very ancient times, these have been used as tests of eyesight. To be able to see Alcor with the naked eye means that one had excellent eyesight. So also on the plains, the old folks would ask the children at night, "Can you see the pappoose on the old squaw's back?" And when ljie youngster saw it, and proved that he did by a right description, they rejoiced that he had the eyesight which is the first requisite of a good hunter. THE PLEIADES One of the oldest of all eye tests is the Pleiades. Poor eyes see a mere haze, fairly good see five, good see six, excellent see seven.