shall descend again, they on whom its crash may fall will not be destroyed before I have warned them; but I pray that their destruction may turn away from us the more terrible judgments of God.

Construct a square A B C D. Join the diagonals A C, B D, and produce them indefinitely both ways. Bisect A B, BC, CD, D A in E, F, G, H. Join EG, FH, and produce them indefinitely both ways. The points E, F, G, H are the centres of the arcs of the quatrefoil, while K is the centre of the circumscribing circle and arcs of circles.

Exercise in Dictation-XI.

The stocks, or public funds, are loans advanced to Government, for which interest is regularly paid from revenues set apart for the purpose. This mode of raising supplies, by levying taxes for the payment of the interest, is called the Funding System,"

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and the loans thus raised constitute the National Debt.

THE MOON.

When the sacred historian speaks of the two luminaries of our system, or rather of our earth, as "two great lights," he does not refer to their bulk or solid contents-for though the sun is the largest body in our system, the moon is one of the smallest-but to the quantity of light which they shed upon the earth, and to the appearance they present to us. The language by which they are designated is striking; for as the sun is the monarch of the day, the moon is the regent of the night, both ruling those portions of time which were assigned to their dominion. It is, indeed, true, that both the planets and fixed stars afford a considerable portion of light, yet they cannot be said to rule or predominate by their light, since their rays are lost in the superior splendour of the moon's illumination.

The moon has been an object of considerable attention among all nations, and in all ages. The ancients regarded her with superstitious reverence. Among the Hebrews she was more honoured than the sun, and they were more inclined to worship her as a deity. The new moons, or first days of every month, were kept by them as festivals, which were celebrated by sound of trumpets, entertainments, and sacrifices.* The people were not obliged on these days to rest. The feasts of new moons were a miniature representation of the feast of trumpets, which was held on the first of the month Tisri, the beginning of the civil year. The Jews, from their ignorance of the nature of eclipses and of their physical causes, looked upon them, whether of the sun or the moon, as signs of the Divine displeasure. The Greeks considered the moon as favourable to marriage. By the Spartans the full moon was held favourable to any undertakings, and nothing could induce them to enter upon an expedition, march an army, or attack an enemy at any other season. The patricians at Rome had such a reverence for the moon, that they wore a crescent on their shoes to distinguish them from the other orders of men.

The moon is a satellite to our earth, constantly attending

* Numbers x. 10; xxviii. 11; 1 Sam. xx. 5-18.

upon it in its annual revolution round the sun, and affording us at certain seasons the most agreeable illumination in the absence of that luminary. She also moves round the earth in an elliptical orbit in 27 days 7 hours 43 minutes, and revolves on her axis in exactly the same time; so that the same side of her is always turned towards us, illuminated in different degrees, according to her relative position with regard to the sun and us; and for the same reason her day and night, taken together, are of the same length as our lunar month. The period from change to change is about twenty-nine days and a half. The moon's light is derived from the sun, and reflected back upon us. Notwithstanding the brightness of her appearance, when at the full, a very slight observation, even with the naked eye, will convince us that her surface is diversified with inequalities and shadows; and this variegated appearance is more distinctly shown by the telescope. The general aspect of her surface is nearly alike every month, but attended with occasional, and even frequent partial variations.

Next to the sun, the moon is, in our view, the largest and most splendid body in the heavens; not on account of her size, for she is much smaller than most of the primary planets, but on account of her nearness to us. To a spectator in the sun, she would be scarcely visible without the aid of a telescope. The diameter of the moon is 2,160 miles; and her distance from the earth, round which she revolves in an elliptical but irregular orbit, is 240,000 miles. Moving at the rate of about 2,300 miles in an hour, she goes round the earth in 27 days 7 hours 43 minutes, and revolves upon her axis in the same period. As the earth is advancing in her orbit round the sun during the moon's revolution, the period from change to change, or from one new moon to another, is extended, and occupies about 29 days and a half. Nothing can be more variable than the appearances of the moon; and the inequality of her motions is as great as the variety of her phases. She comes to the meridian, or south, every day later than the preceding, and the differences are very unequal: she has also very different altitudes when on the

meridian. Sometimes she enlightens us the whole night; at other times she does not appear till late at night, or early in the morning; and frequently she is absent altogether. Sometimes she keeps in the southern region of the heavens; at others, she rises higher and higher in the northern hemisphere. But all these mutations of the 66 changeful moon are ascribed to known and certain causes, constantly and effectually operating, and are predicted with as much accuracy as those of the other planetary bodies, though attended with more labour in the computation.

Though the same face of the moon is always turned towards us, it is not with perfect uniformity, for she sometimes turns a little more of the one side, and sometimes of the other, which is termed her libration; and the same thing takes place in another direction, by a motion like a kind of wavering or vacillation, whence it happens that sometimes the one, and sometimes the other, pole of the moon becomes visible.

The orbit of the moon is not parallel with that of the earth, but is inclined to it in an angle of 5 degrees 18 minutes, cutting it in two points which are diametrically opposite to each other: these points are called her nodes. These nodes do not occur successively in the same parts of the orbit, but have a motion westward, contrary to the order of the signs, making a complete revolution in about nineteen years, which constitutes the lunar cycle, when each node returns to that point of the ecliptic from which it had receded.

From the nature of the moon's motion, it will appear obvious that she is once every month between the earth and the sun, or in conjunction; and once on the opposite side of the earth, or in opposition. In the former case, when in or near the nodes, so as to be sufficiently in a line with both, an eclipse of the sun takes place ; in the latter, an eclipse of the moon.

It is remarkable that the moon, during the week in which she is full about the time of harvest, rises sooner after sun-setting than she does in any other full-moon week in the year. By this means she affords an immediate

supply of light after sunset, which is very beneficial for the harvest, and gathering in the fruits of the earth— hence the term harvest-moon.

To conceive the reason of this phenomenon, it may be considered that the moon is always opposite to the sun when she is full; that she is full in the signs Pisces and Aries in our harvest months, those being the signs opposite to Virgo and Libra, the signs occupied by the sun about the same seasons; and because those parts of the ecliptic rise in a shorter space of time than others, as may easily be shown and illustrated by the celestial globe; consequently, when the moon is about her full in harvest, she rises with less difference of time, or more immediately after sunset, than when she is full at other seasons of the year. When she is in that part of her orbit in other seasons, she gains as much in her time of rising, but then it is either at the new moon or at one of the changes; but in autumn this happens at the time of her full, so that she rises soon after sunset for several evenings successively, which makes her regular rising very conspicuous at that time of the year, and affords an instance of merciful design.

Another remarkable circumstance is this, which almost everyone must have observed, that the moon at rising and at setting, but especially the former, appears much larger than at a considerable height above the horizon. This phenomenon is merely due to an optical delusion, arising from the apparent proximity of the moon to the horizon and objects on it. The same appearance is observable in the sun, though not in so great a degree.

The connection of the moon with our earth, her service in often affording us light in the absence of the sun, in subdividing the year into months, regulating the flux and reflux of the sea, and the various phenomena she presents to our notice render her an object of much interest to the navigator, the traveller, the husbandman, the astronomer, and the contemplative observer of nature's works, or rather of the wonderful operations of Him who “filleth all in all."