are the means of making a comparison of the degree of cold, that has prevailed at different times.

The year is naturally divided into four periods by the equinoxes and solstices, or those epochs when the day is equal to the night, namely, 21st of March and 23d of September, and those when there is the greatest difference, namely, 21st of June and 22d of December. Our Winter, Spring, Summer, and Autumn, have reference to these epochs, although their commencement and termination does not correspond exactly to the astronomical times above indicated.

We are apt to imagine, that the four seasons are equal to each other, and that spring and summer are together just half the year. This is not the case, however, more especially with respect to the natural periods so deminated. If, for example, we compare the time from the 21st of March to the 23d of September, with the rest of the year, we shall find a difference of about one week, the former being the longer. We may thus be said to have a week more summer than winter. But this benefit of a long summer is confined to the northern hemisphere, which is so distinguished by natural advantages, and not less certainly by moral and political ones. We must not forget, however, that this natural distinction is not a permanent one, whatever the others may be. This longer continuance of the sun in the northern hemisphere arises from the particular position of the sun's oval orbit, or path through the heavens. We have already stated, that the sun is nearest to us in the winter season; in other words, the earth is nearest to the sun, and on this account its motion is more rapid, so that the part of the orbit from the autumnal equinox (September 23d) to the vernal (March 21st), is completed a week sooner than the other half, in which the motion slower. But the point of the sun's nearest approach, or perihelion, on the position of which the above mentioned physical advantages depend, is in motion, whereby we are gradually losing the benefit of a prolonged summer, and in about 5000 years shall cease to enjoy any such privilege. In about 10,000 years the condition will be reversed, and the southern hemisphere will be the favored portion of the globe. It may be worth mentioning, that at the date fixed by chronologists for the first residence of man upon the earth, the sun's influence was equally distributed to the two hemispheres.

V. THE ZODIAC.

THE term zodiac comes from a Greek word signifying animal, because most of its divisions are named after certain animals. It is a broad zone or belt in the heavens extending each way from the ecliptic, or sun's path, so as to comprehend the orbits of all the planets that were known to the ancient astronomers. It is divided into twelve parts, answering to the

twelve months of the year, or twelve revolutions of the moon. These divisions of the zodiac comprehend certain collections of stars, and are thence denominated constellations. They are also called signs, because they indicated, as the sun approached them, or was in them, the season of the year; and thus, before almanacs were invented, they were of great importance as a guide in the labors of the field. These divisions began at the vernal equinox, or point in the spring where the sun is when the days and nights are equal all over the earth, which, in the temperate climates of the northern hemisphere, is about the beginning of the season of vegetation, and corresponded nearly, in ancient times, to the beginning of the year. The first divisions, Aries, Taurus, Gemini, in which the sun is from the 21st of March to the 21st of June, indicated the season of reproduction. The 4th sign, Cancer, the Crab, an animal that moves sideways and backward, commences at that point of the sun's annual course in which he begins to move back toward the south. The 5th sign, Leo, is thought to denote the period of the sun's greatest power. The 6th sign, Virgo, which is represented by a female with an ear of corn in her hand, is supposed to be descriptive of the season of harvest. The sign Libra, is probably so named from the circumstance that the sun, when it enters this sign, imparts equal day and night to all parts of the earth. The Scorpion, or 7th sign, may have been intended to mark that part of autumn in which diseases are most prevalent. Of the remaining signs, Sagittarius is understood to mark the season of hunting; and Capricornus the point in the ecliptic from which the sun begins to mount toward the north. Aquarius and Pisces have been explained as referring respectively to the rainy season and the season of fishing.

It is a great mistake to suppose, as some are apt to do, that there is any resemblance between the collections of stars belonging to these signs and the animals whose names they bear. There is some foundation for such a supposition with regard to some of the constellations out of the zodiac, as the Swan, the Crown, &c. But with respect to those of which we have been speaking, and most of the constellations in other parts of the heavens, no such idea probably ever entered into the mind of the persons who first gave them their names.

The signs and constellations, commencing as they both did formerly at the vernal equinox, coincided with each other throughout the zodiac. But the equinox is continually shifting backward, contrary to the direction of the sun's annual motion, thus departing farther and farther from the stars which once occupied their place. But the first division of 30°, reckoned from the equinox, is still called Aries, the second Libra, &c., since they continue to denote the same season. They are, however, no longer the same constellations. The collections of stars, known by these names, are left far removed from the part of the sun's path in which they formerly indicated a particular season. The sun enters the sign Aries on the 21st of

March, but it does not enter the constellation Aries till a month later. Still the sun, on entering the sign Aries, brings with it the same season that it did 2000 years ago, when it entered the sign and constellation at the same time. By this retrograde motion of the points on which the seasons depend, known by the name of the precession of the equinoxes, the signs have withdrawn from the constellations about one-twelfth part of the whole circuit of the heavens, and in 24,000 years more, they will have gone entirely round, so as to resume their former places. Hence it will be seen that, although the ancients made use of particular positions of the stars with respect to the sun, as their rising just before the sun, or their setting just after it, as indicative of the seasons, yet this method would lead to great errors after the lapse of a considerable period.

VI. ASTROLOGY.

THE greatest absurdities that have prevailed in the world, if thoroughly examined, will be found to have some decent apology, some plausible foundation; for they have been received with favor by men of the same nature with ourselves. It is admitted on all hands, that the heavenly bodies determine our physical condition. The obliquity of the ecliptic, the precession of the equinoxes, the progressive motion of the apsides, the nutation of the earth's axis, may be mere sounds to most ears; but, understood or not, they stand for facts, the influence of which is felt by all. Whether a man shall be 4 or 6 feet high, whether he shall be, in strictness of language, a rational being, or a mere slave of his passions, may depend upon the latitude in which he happens to be born. Not only the plague, the yellow fever, the malaria, the sirocco, and east wind, are determined by geographical limits, but also, to a greater or less degree, moral and political diseases, the contagion of licentiousness, and the storms of the passions. The physical man and the moral man are united by the closest communication and sympathy. They are, like the Siamese twins, bound to each other by a strong and indissoluble tie. Now the material frame, with its exquisite structure, its wonderful mechanical contrivances, and fine organs of sense, grows up like animals and plants, by a continual accession from surrounding matter. It is nourished and matured by fire, air, earth, and water. As a greater degree of heat accelerates the progress of a plant, so a tropical sun brings to maturity those physical and intellectual powers, which require twice the number of revolutions of the sun to perfect them in a more northern clime, where his rays exert but half the energy. Thus the developement of mind, like the opening of a flower, takes place sooner or later, according to the state of the thermometer; moreover, in the subsequent period of manhood, the more or less perfect predominance of reason

and the higher principles of our nature, is intimately connected with the physical character of the world about us.

It will not be denied, that whatever belongs to soil and climate, to scenery, to animal and vegetable productions, to the air we breathe, and the light by which we see, is derived more or less directly from celestial influences. Day and night, summer and winter, seed-time and harvest, with their mighty train of consequences, are the simple and natural results of our different positions with respect to the sun. This has been felt by those who have attained to little that deserves the name of science; and it required but little observation and study to be able to predict the return of the same season, and the time of the rising and setting of the sun. A longer series of observations and more elaborate calculations, resulted in foretelling also the particular aspects and positions of other heavenly bodies. At length the wonderful phenomena of eclipses of the sun and moon, were announced, long before they took place, with a degree of truth and exactness, that astonished the world. This being accomplished, it was an easy transition in the minds of the mass of mankind, in an unenlightened age, to extend this prescience and foresight to other natural events, as earthquakes, famine, and pestilence. Those who could predict the extraordinary phenomena of eclipses, might well be presumed to understand every thing relating to such minor occurrences as rain, hail, and snow, winds and tempests; and in an ignorant age, and among a debased and credulous people, such predictions would be readily confounded with those of a moral and political nature.

Our knowledge extends to the future with respect to those events, all the causes and circumstances of which we perfectly understand. Eclipses of the sun and moon, planets and stars, depend simply upon their relative positions. Now the motions of these bodies result from a few simple laws, which we have succeeded in discovering, so as to be able to tell where one of these bodies will be at any particular time, almost to a hair's breadth. We are thus able to predict eclipses accurately, and men rely fully upon these predictions, because they have so long been found by the experience of the world to prove true. Now the motion of the air, or wind, depends upon the same general principles, as the motion of the heavenly bodies. But here on the earth there are, for the most part, so many things to be taken into consideration, that we are unable, except in some of the most simple cases, to anticipate the result. We could predict the motion of a cannon ball as we do that of a planet or a comet, if the air were removed, and we knew the initial velocity and direction; and we can allow for these modifying circumstances according to the accuracy of our knowledge of these circumstances. We can also predict, to a certain degree, the direction, velocity, &c. of the wind in certain parts of the earth, as between the tropics, on small islands, &c. where we are acquainted with all the leading circumstances of the phenomena. But in the temperate latitudes

the causes affecting the direction and force of the wind, are very numerous, and too imperfectly known, to admit of any such attempt. We can calculate accurately the length of a particular day at any place, and the altitude of the sun at any hour of the day. In other words, we can state accurately the general causes which determine the temperature of such a day in such a place. But there are many modifying circumstances, as the direction of the wind, the clearness of the atmosphere, &c. which we cannot take into consideration; and therefore we can predict the temperature only in a general way, without being able to say precisely at what degree the thermometer will stand.

Fair weather and foul are the result of so many causes, some of which, as the chemical changes that are going on in the atmosphere, are so imperfectly understood, that we can make no pretensions whatever to foreknowledge in these particulars, as we do in regard to eclipses. There are, it is true, certain states of the air, and certain appearances in the heavens, that are generally followed by a change in the weather; and a long habit of observation may enable seamen and others deeply interested, to anticipate the weather for a few hours. But no one can lay claim to such knowledge a week beforehand, and still less in season to insert it in an Almanac. All such predictions, therefore, from whatever authority, are to be regarded as a species of quackery, the relics of astrology, of a system of fraud, which the selfish and designing are always ready to practise upon the credulous and unthinking part of society.

Some of our Almanacs continue to give the name of dog-days to a certain period extending from the latter part of July to the beginning of September; and many persons perhaps still believe, that the Dog-Star, or Sirius, has something to do with the warm and sultry weather which we usually have at this season. The fact is, that the sun was formerly in the neighbourhood of this star at this time of the year; and before other and better means were devised, the near approach of the sun to a star was used to denote the season. Two thousand years ago it so happened, that the sun passed this star in the warmest part of summer. But it does not pass it so soon now by a month, on account of the precession of the equinoxes, and in about 8000 years, it will be later still by five months, and dog-days would happen in the middle of winter. Aware of this, Almanacmakers were in doubt for some time whether they should give the name of dog-days to the warmest part of summer, or to the time when the sun is near this star. But finding at length, that if they conformed to the original idea, they should gradually carry this period into autumn, they left the star, and returned to the season intended to be marked by it.