us see if, by some other means, by images or comparisons, we can appeal to our senses to comprehend this fact: What is this distance of 186,000 miles which light traverses in a second? This distance is an abyss to our imagination. But suppose we could grasp, as in a bird's-eye view, this distance; let us associate it with the short duration of a second; and then let us imagine that a single day of twenty-four hours contains 86,400 such intervals; and let us stay to contemplate the enormous distance to which the luminous ray would arrive after a day's journey-it will have plunged into space to a depth seven times greater than the distance of Neptune. Still, according to what has been just stated, it would not have accomplished the thousandth part of its route; it must continue its course of 1,300 days with the same tremendous velocity before it could reach the nearest star-Alpha Centauri. Such, in every direction, are the dimensions of the space devoid of stars which surround our Solar System. From the measurements already made, we may say that on the average light requires fifteen and a half years to reach us from a star of the first magnitude, twenty-eight years from a star of the second, forty-three years from a star of the third, and so on, until, for stars of the twelfth magnitude, the time required is 3,500 years. We find the largest stars scattered very irregularly, but if we look at the smaller ones, we find that they gradually increase in number as their position approaches the position of the sky occupied by the Milky Way. In fact, of the 20,000,000 stars visible, as just stated, at least 18,000,000 lie in and near the Milky Way. Adding this fact to what has been said about the distances of the stars we can now determine the shape of our universe. It is clear that it is most extended where the faintest stars are visible, and where they appear nearest together; because they appear faint in consequence of their distance, and because their close packing does not arise from their actual nearness to each other, but results from their lying in that direction at constantly increasing distances. Indeed, the stars give rise to the appearance of the Milky Way, because in that part of the heavens they lie behind each other to an almost infinite distance, are probably as far from each other as our Sun is from the nearest star. One thing more I wish to mention: that is, the motions of the stars. Now, although the stars, and the various constellations, retain the same relative position as they did in ancient times, all the stars are, nevertheless, in motion; and in some of them nearest to us this motion, called proper motion, is very apparent, and it has been measured. Thus, Arcturus is traveling at the rate of at least fifty-four miles a second. Nor is our sun, which, be it remembered is a star, an exception; it is approaching the constellation Hercules at the rate of four miles a second, carrying its system of planets, including our Earth with it. The Zodiac, as viewed by the ancients, consisted of twelve constellations of stars, lying along the plane of the ecliptic, a line through which the Sun passes every year. In English and in rhyme these are as follows: "The Ram, the Bull, the Heavenly Twins, The Virgin and the Scales, The Scorpion, Archer, and He-Goat, And in Latin they run thus: "Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio, Sagittarius, Capricornus, Aquarius, and Pisces." The celestial equator is represented by a circle called the Zodiac, which not only divided, like all other circles, in to degrees, etc., but into signs of thirty degrees each. The names of these signs. appear above. At the time these signs were adopted the Sun entered the constellation Aries, at the vernal equinox, and occupied in succession the constellations bearing the same names; but at present, owing to the precession of the equinoxes, the signs no longer correspond with the constellations, which must, therefore, not be confounded with them. By precession of the equinoxes is meant a slight retrograde movement of the nodes; that is to say, the Earth's equator crosses the line of the ecliptic a little farter back in the Zodiac each year. The Moon, too, is affected by the precession of the equinoxes, as is the Earth; and so, too, I believe, are all the planets of the Solar System. I do not consider it necessary in this work, to give more than a brief outline of the science of astronomy, and such facts in particular as are necessary for the work in hand. Those persons who wish to pursue the subject further I would refer them to the many good books published on astronomy, books that are written by more able authors than myself. I must say in passing, however, that I am largely indebted to Mr. A. Guillemin and Professor J. N. Lockyer for the information contained herein. Plates I. and II. are taken from Guillemin's "The Heavens." CHAPTER II. THE SOLAR SYSTEM. The group, or system, of celestial bodies, of which the Earth forms part, a system known in astronomy under the name of the Solar, or Planetary System, is composed, according to our present knowledge, of about two hundred bodies, which may be classed in the following manner: I. A central body, relatively immovable in the group, much larger than all the others and self-luminous, The Sun. 2. One hundred and sixty-eight secondary bodies, or planets, situated at increasing distances from the Sun, revolving round him in orbits nearly circular, and receiving from him the light which renders them visible to us. The planets may again be divided into three principle groups. The smaller planets, those nearest the central body, are, in the order of their increasing distances from the Sun, Mercury, Venus, the Earth, and Mars; The larger planets, those most remote from the central body, Jupiter, Saturn, Uranus, and Neptune; Lastly, the minor planets, or Asteroids, forming between Mars and Jupiter a ring, which separates the two first groups. About one hundred and sixty or more of these small planets are now known, but there are, no doubt, many more. 3. Twenty-one tertiary bodies, or satellites, revolving round some of the principal planets, such as the Moon, which accompanies the Earth. Jupiter has seven such satellites, Saturn eight, Uranus four, Neptune one; Mars, it is claimed by some astronomers, has two. 4. Fifteen comets, the periodical returns of which have been proved by observation, revolving round the Sun in very elongated orbits. We must here also mention a nebulous ring of lenticular form, the Zodiacal Light, which surrounds the Sun at a certain distance, and the position of which in the system is not yet clearly determined; and, besides this, hundreds of rings composed of multitudes of small bodies revealed to us by the appearance and fall of Meteorites, Meteors, and Falling or Shooting Stars. The direction of movements of revolution is the same for all the bodies of the Solar System, and this direction is precisely that of all movements or rotation. In order that the reader may grasp this important point, let him turn to Plate I., which represents the orbits of all the known planets. The arrow in each case indicates the direction of the planets' revolution round the Sun. Plate II., on the same sheet, gives the inclination of the orbits of the planets to the plane of the ecliptic. As is seen, by Plate I., the movement indicated by the arrow takes place from right to left. But, to make this plainer, if we hold up a clock with the face toward the north, the movement of the hands is from left to right, or from east to west. Now the planets move in precisely the opposite direction to that which is described by the hands of the clock; that is, from right to left; of from west to east. So let us remember, once for all, this fundamental fact of solar astronomy, that the movements, both of rotation and of revolution, of the planets and their satellites, are affected all in the same direction; that is, from right to left, or from west to east. The ideal curves described by the various planets round the Sun, considered at rest, are plain curves, or at least nearly so. This plane, if prolonged, passes through the center of the Sun. But the planes of those orbits do not coincide with one another. They are differently inclined to that of the Earth, taken as a standard of comparison; from this it results, that each planet describe: half its orbit above the plane of the terrestrial orbit, or, as it is called, the plane of the ecliptic, and the other half below it. The inclinations, represented in their true proportions in Figure 2 of the plate just mentioned, are very small; and it follows that, as seen from the Earth, the principal planets revolve in a narrow zone of the celestial vault. This zone has received the name of the Zodiac. Having taken a general view of the Solar System, it will be necessary now to examine it briefly in detail. We will begin with THE SUN. Which dazzles the whole family of planets by its brightness, supports their inhabitants by its heat, and keeps them in bounds by its weight. The relative brilliancy of the center of our system, compared to that of the stars, is so great that it is difficult at first to look upon it as in any way related to those feeble twinklers. This difficulty, however, is soon dispelled when we consider how near it is to us. Thus, to give another instance, though we receive 10,000,000,000 times more light from the Sun than we do from Alpha (a) Lyrae, that star is more than a million times further from us. There is a reason to believe, indeed, that our Sun is by |