around the sun, it takes the moon two days longer to regain the position it started from, making 29 days in all.

Phases of the Moon.-When the moon is new, forming a delicate crescent, it is said to be in its first quarter. As it continues in its progress towards the East, it becomes gibbous (which means more than a half, and less than the whole of a circle) until the 15th day, when it reaches a point in the heavens directly opposite the sun, and is then said to be in opposition, where its entire illumined side is toward us, and is called full roon. As it decreases in size it passes into the third quarter, until it

reaches a point in the heavens, where it turns towards us the dark side, and keeps on decreasing, until it becomes a crescent again.

The Harvest Moon is so called because the moon rises about 50 minutes later each night, although the exact time varies from a half to a full hour, due to the fact that the moon's path is not always at the same inclination to the horizon at different seasons of the year.

When the moon passes in front of a star so that the star disappears on

one side and reappears on the other it is called an occultation.

The moon has more than 1000 mountains, some of which exceed

25,000 feet in height, and the ranges extend for hundreds of miles. It also has gray plains or seas similar to our prairies. These were formerly

thought to be sheets of water, but inasmuch as they exhibit the uneven appear ance of plains in stead of the curved appear ance of the se they are now sup posed to be the former.

An Eclipse of the Sun is due to the fact that the moon comes be. tween the earth and the sun. The shadow of the moon is called the umbra, and all within it experience a total eclipse, while those who are outsidethe deeper

shadow and within the lighter shadow (the penumbra) witness only a partial eclipse.

The Eclipse of the Moon is due to the fact that it is in opposition and passing through the earth's shadow.

The Tides are caused by a great wave, raised by the moon's attraction, which follows it in its course around the earth. The sun aids somewhat in producing this effect, but notwithstanding the fact that the sun is so much larger, the moon is 400 times nearer the earth, and, therefore, its influence is greater than that of the sun.

MARS.

Mars, which is called the "God of War," is the first of the planets outside of the earth's orbit, and is also the first of the class of superior planets, Mercury and Venus, completing the order of inferior ones.

Mars appears as a bright red star. It revolves around the sun at a mean distance of about 141,000,000 miles. Its orbit is flattened, so that at perihelion it is 26,000,000 miles nearer to the sun than at its aphelion. Its average velocity is about 15 miles per second. Its day is 37 minutes longer than ours. Its year consists of about 687 terrestrial days. When Mars is in opposition; that is, when the earth is between it and the sun, it is about 34,000,000 miles from the earth. Its diameter is nearly 4200

miles. A stone falling on its surface would tail 6 feet the first second. Its shape is much like that of the earth. The light and heat that Mars receives is about one-half of that which we enjoy. Its atmosphere is like our own, loaded with

clouds. It has two moons. Its surface is covered with red spots supposed to be continents.

One of the differences between Mars and the earth is that on the earth every continent is an island, whereas on Mars every sea is a lake. The red color is thought by Herschel to be due to ochre in the soil; one astronomer suggests that the color of the plants and trees is red in place of green. No mountains have yet been discovered. It is thought by many to be inhabited.

MINOR PLANETS.

Beyond Mars, and this side of Jupiter, there have been discovered 247 small planets, of which Ceres is one. Leverrier has calculated that there may be perhaps 150,000 in all. These " 'pocket planets," as Herschel calls them, are very small indeed; the largest of them, Vesta, can be seen at times with the naked eye. Those discovered most recently are so small that it is hard to tell which is the smallest. It is said that a good walker could easily walk around one in a day. A man on one of these tiny spheres could jump 60 feet high, and on falling would sustain no greater shock than by leaping a yard on the earth. They are supposed to le fragments of some larger planet that away back in remote antiquity was shivered to pieces by some terrible catastrophe.

JUPITER.

Nature delights in contrasts, and from these diminutive specks we pass to the largest planet, Jupiter. It is one of the five planets discovered in the earliest times. It revolves about the sun at a mean distance of about 483,000,000 miles. Its progress through the heavens is at the rate of about one year to each sign of the Zodiac, so that its years are about twelve times the length of ours, comprising about 10,000 days. Its speed is at the rate of nearly 500 miles per minute. Its diameter is about 90,000 miles. Its volume is 1400 times that of the earth. If it were at the same distance from the earth as the moon it would appear to occupy Ioco times the space of the full moon. The rotation of Jupiter on its axis is at the rate of 473 miles per minute at the equator, whereas that of the earth is 17 miles. Its seasons are but slightly varied. Summer reigns at the

equator, while the temperate regions enjoy perpetual spring. The light it receives from the sun is about one twenty-seventh of what we get. Jupiter has four moons, named as follows: Io, Europa, Ganymede and Callisto.

Io revolves around Jupiter at a mean distance of 267,380 miles; its diameter is 2352 miles.

Europa revolves around Jupiter at a mean distance of 425,156 miles; its diameter is 2009 miles.

Ganymede revolves around Jupiter at a mean distance of 678,393 miles; it diameter is 3436 miles.

Callisto revolves around Jupiter at a mean distance of 1,192,823 miles; its diameter is 2929 miles.

It is supposed that Jupiter is enveloped in dense clouds, and that it has belts or dusky streaks of varying breadth and number lying nearly parallel to the equator. In 1878 a red spot appeared in the southern hemisphere, which it was estimated was 200 miles broad and 8000 miles long. This is still visible, but is much dimmer.

SATURN.

The most remote world known to the ancients was Saturn, which requires two-and-a-half years to pass through a single sign of the Zodiac. It has eight moons, besides being surrounded by a system of rings. It revolves around the Sun at a mean distance of about 886,000,000 miles. It moves at the rate of 22,000 miles per hour, yet it takes about thirty years for it to revolve around the sun. It is about 73,000 miles in diameter. The light and heat which it receives is about one one-hundredth of that which we get.

SATURN.

Its seasons are similar to those of the Earth, but on a larger scale. There is a difference of fifteen years between spring and autumn equinoxes. For fifteen years the Sun shines on the North Pole, and the same is

experienced by the South Pole. Its atmosphere is very dense. At first, before its rings were discovered, Saturn was supposed to have a handle attached to it.. It has three rings of unequal breadth surrounding the equator. The exterior ring is separated from the middle one by a distinct break, while the interior ring seems to join the middle one. The exterior ring is of a grayish tint, the middle one is almost more luminous than Saturn itself. The interior one is dark and has a purplish tinge. The outer rings are bright, but the inner one is called the dusky ring. The onter and middle ring are opaque, and cast a shadow upon the planet.

The inner one is transparent. These rings revolve around Saturn in about ten-and-a-half hours, in the same direction as the planet. It is now generally believed that the rings consist of a cloud of tiny satellites, too small to be seen even with a telescope.

It is now generally believed that Saturn, like Jupiter, has no solid crust, but consists of a mass of molten matter surrounded by vapor which rises from the heated surface.

Saturn has eight moons, which are as follows:

Mimas, revolving around Saturn at a mean distance of 120,800 miles; having a diameter approximating 1000 miles.

Encaladus, revolving at a mean distance of 155,015 miles; diameter not known.

Tethys, revolving at a mean distance of 191,248 miles; approximate diameter 500 miles.

Dione, revolving at a mean distance of 245,876 miles; approximate diameter 500 miles.

Rhea, revolving at a mean distance of 343,414 miles; approximate diameter 1200 miles.

Titan, revolving at a mean distance of 796,157 miles; approximate diameter 3300 miles.

Hyperion, revolving at a mean distance of 1,006,656 miles; approximate diameter not known.

Japetus, revolving at a mean distance of 2,313,835 miles; approximate diameter 1800 miles.

URANUS.

This planet was discovered by Sir William Herschel, March 13, 1781, and it sometimes bears his name. It is seen with difficulty, owing to its great distance from our earth. It revolves around the sun at a mean distance of 1,782,000,000 miles, and its year is equal to eighty-four of ours. Its diameter is about 33,000 miles. Its density is about equal to that of water from the Dead Sea. Little is known about its seasons. The light and heat it receives is about roof that which we receive. The light it is estimated would be about as great as that afforded by 300 Full Moons. Little is known of the other features of Uranus, except that it has four Moons, that move contrary to our Moon; they revolve in the opposite direction like the hands of a watch.

NEPTUNE.

This is the most distant planet of our system, and is invisible to the naked eye. It was discovered in the following manner: For years the motions of Uranus were contrary to what astronomers had a right to expect; finally they came to the conclusion that there must be a planet outside of its orbit, whose attraction was so great it caused these disturbances. At length two young men, Leverrier, of Paris, and Adams, of Cambridge, England, set to work, unknown to each other, to find the place of this new planet. Adams, after two years calculation, submitted a paper to Prof. Airy, the Royal Astronomer, in 1845. Leverrier, in the summer of 1846, laid his paper before the Academy of Sciences in Paris. Prof. Airy, learning of Leverrier's work, was so impressed with the results