This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1874 edition. Excerpt: ... THE TRANSIT OF VENUS. CHAPTER 1. IN days of old it was supposed that the earth held the central position of the solar system, and that moon, sun, and planets moved round it, each in its own orbit. The moon was supposed to be nearest to us, then came Venus, then Mercury, after that the sun, then Mars, Jupiter, and Saturn. We now know that of all these the moon is the only one which revolves round the earth, and that all the planets travel round the sun in paths at different distances from it in the following order, the first being that nearest the sun: -- Mercury, Venus, the Earth, Mars, Jupiter, Saturn. These are all the planets which were known to the ancients. Since Mercury and Venus were formerly supposed to be lower than the sun, and all the others higher, the name of inferior planets was given to the former, and superior planets to the others. These terms are still retained by astronomers, though the ideas that gave rise to these terms are long since exploded. Fig. I shows the appearances presented by Venus, one of the inferior planets, in the course of its journey round the sun. V is the planet. E is the earth, which is shown in the figure always in one position, although of course it also describes an orbit round the sun. We are naturally led by a study of the diagram to three points of interest concerning the motions of an inferior planet. The first is that the planet can never seem to be far distant from the sun. Venus moves round the sun in the direction shown by the arrow. The earth rotates in the same direction. We are supposed to be looking down upon the solar system from some point in the northern heavens. It will be noticed that when the planet leaves the point Vj, she will seem to recede from the sun more and more, until...