́zone; but this constellation is not the cause of the heat, which is occasioned by the sun being then at its greatest elevation; and in the opposite zone, when the dog-star rises with the sun, it is altogether as cold: so that the inhabitants of the southern countries, far from considering the dog-star as the cause of heat, regard it as the cause of cold. The same may be said of the Pleiades, which are supposed to bring rain, and of all the constellations to which effects are attributed that really belong to the seasons in which these stars rise or set.

If, then, the planets and fixed stars have no part in the temperature and natural dispositions of our globe, they must still have less influence upon human actions. The happiness and the misery of individuals, and of whole nations, partly depend upon their natural talents and passions, and in part upon the political constitution of states, and upon the combination of certain natural and moral causes: consequently, the stars can have no influence whatever upon these, and if they had, we should have some reason to doubt the empire of Providence, and to disbelieve in the agency of a Being infinitely wise, good, powerful, and just. Leav ing, then, to the superstitious a science so inimical to our repose, and so humiliating to the human mind; a jargonistic cant, disgracing the name of science, called by its advocates judicial astrology, and which in fact is nothing more than a miserable abuse of astronomy in the hands of knaves and of impostors, or of weak and foolish people; let us look up to our wise and merciful Parent, as the only true foundation on which to rest the certainty of our present peace and eternal happiness.

DECEMBER XX.

The Polar Star.

THE most remarkable among the northern constellations is that which is nearest to the north-pole, and termed the little bear. The last star of its tail is but two degrees from the pole; hence it is called the polar star. It is easily distinguished from the neighbouring stars, because it scarcely ap pears to change its position, and is always in the same part

of the heavens: for though it revolves round the pole, its motion is so slow, and the circle that it describes so small, as to be scarcely perceptible. By this apparent fixity of situation, it becomes a guide to travellers, and particularly to mariners who are sailing on the open seas. Before the discovery of the compass, sailors had no surer guide than the polar star; and even now when the sky is serene, they repose in many cases with greater certainty upon the direction of this star than upon the magnetic needle.

The advantages which we derive from the polar star naturally lead us to the consideration of that moral guide and inestimable gift that God has bestowed upon us, his blessed word, and particularly the Gospel, which points out to us with unerring certainty the path that we ought to follow, and the true course in which to steer upon life's stormy ocean, through the gloom that darkens our way. Without such a faithful guide we should wander in uncertainty, and never find the path that leads to God and celestial glory. In the Divine relation alone do we find a certain and invariable rule, by which we may pursue with courage and assiduity, the race that is set before us, and accomplish it with joy and felicity.

Let us attend to this, as the pilot attends to the polar star, and, by continually keeping it in sight, prevent the possibility of erring. With this heavenly guide we shall shun all dangers, be preserved from shipwreck, and after our long and arduous voyage at length happily arrive in that blessed haven where we shall rest from all our labours, and enjoy a happiness which nothing can molest or disturb.

The preceding reflection on the polar star is also calculated to make us admire the goodness of God, who, by the position and the course of the stars, has given us the means of knowing the times, places, and different points of the heavens. An astronomer, though in an unknown country, can, by means of the stars, know where he is; and can inform himself of the month, the day, and the hour, with the same certainty as if he had consulted the most correct timepiece. If, for instance, we observe that the stars every day are seen four minutes sooner at the place where they were on the preceding evening, we know that in a month it will amount to two hours. Thus the star that we see this even

ing, the 20th of December, at ten o'clock, in a certain part of the heavens, will be seen on the 20th of January exactly in the same place at eight o'clock.

DECEMBER XXI.

Effects of Air when confined in Bodies.

THE effects of air, enclosed in bodies, are very remarkable. The consequence of fluids freezing is well known. Water, in the act of congelation, often bursts the vessels which contain it. The barrel of a gun, filled with water, its entrance being hermetically sealed, when the cold is severe, bursts with great violence, At first this appears to be incomprehensible: we know that water is not of itself fluid, but becomes so by the caloric which every where pervades it, and consequently, when deprived of the matter of heat which it contains, becomes a solid mass. It should seem, then, that in their state of congelation, the particles of water must be condensed, and approach nearer to each other, and thus occupy less space than before they were frozen. On the contrary, at the time of freezing they dilate, and their volume increases, otherwise it would be impossible for the vessels to burst. Besides, how could ice swim, if it did not form a greater volume, and become lighter than when in a state of water?

What, then, is the cause of this singular effect? Internal air; for it is impossible to suppose any external cause. To be convinced that it is owing to the air contained in the water, we have only to observe that fluid when it first begins to freeze. Scarcely is the first pellicle of ice formed when the water becomes agitated, and a number of air bubbles ascend. This upper coat of ice often rises in the middle and splits; the water springs up through the cleft, dashes against the sides of the vessel, and in running down again is frozen; thus giving the appearance of elevation and convexity to the middle of the surface. These effects are produced by the air contained in the water, and would not take place, or at least would appear in a much less degree, if, before the water began to freeze, it was exhausted as much as possible of the air which it contained.

On this principle we may explain many singular phenomena. A severe cold is very injurious to vegetables. We know that in all plants the sap circulates; which, though it becomes rather more viscous in winter and in autumn, nevertheless continues fluid. An intense degree of cold converts it into ice, and then evidently increases its volume which cannot take place without causing several fibres and stalks of plants to burst. When this is the case, it is clear that when the sap becomes rarefied in spring, it cannot circulate as it ought to do, no more than the circulation of the blood can be carried on in an animal whose veins are cut. Thus the growth of the plant is prevented, and it dies, because the nourishment juice can no longer flow through its vessels.

From all this we may be convinced of the power of the air, and of that expansibility from which we derive so many advantages. The property that this element has of condensation and of rarefaction, to an almost incredible extent, is the cause of the greatest revolutions that happen upon the earth. It is only in a very few instances that the power of this fluid can become injurious, and then the evils which result are amply compensated by the advantages, We must, however, confess that in this, as in every other phenomenon of nature, there are many things which we are unable to explain: great part of our knowledge of the nature, properties, and effects of air is conjectural, and perhaps it is reserved for succeeding generations how false and erroneous our opinions upon this and many other subjects have been. Whenever, therefore, we contemplate the works of God in nature, let us examine them with caution, and investigate them with a mind humble, conscious of its own inefficacy, and ever mindful of the limited extent of our understanding, and the uncertainty of human judgment or opinions,

DECEMBER XXII.

Music.

To music we are indebted for one of the purest and most refined pleasures that the bounty of heaven has permitted to cheer the heart of man. As it softly steals upon our ear, it lulls to VOL. II.

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rest all the passions that invade our bosom, arrests our roving fancy, or in louder strains excites the soul to rage. Often, when wrapped in melancholy, the sweet voice of music charms away our cares, and restores our drooping spirits, or awakens in us the sentiments of honour and of glory. And surely that which can assuage our griefs, pour balm into our perturbed breast, and make us forget our sorrows, is deserving of consideration, and should be made use of to glorify our beneficent Creator.

Whence proceeds the impression that music makes upon the ear? It is the effect of certain undulations of the air, which strike diversely upon the auditory nerve. When a light cord is pulled, its figure changes; for from its elasticity it not only regains its first situation, but advances beyond it, and continues vibrating backwards and forwards until it recovers its original position and state of rest. These vibrations of the cord are communicated to the air, which conveys them to other contiguous bodies. Thus, when an organ is played upon, if a lute be near, its strings will be put in motion, and make a sound. But whence proceeds the variation of sounds, and how is it that some are sharp and others flat? This is not owing to the quantity of air that is put in motion; for a sound may be flat or sharp, and at the same time strong or feeble. The differences of flats and sharps depend upon the greater or less rapidity of the vibrations of the air. A sonorous body emits a sharp tone when the vibrations are very quick, and a flat when they are more slow. Whence is it that certain sounds are harmonious, and charm the ear, whilst others offend by their discord? All that we can reply to this is, that the natural character of consonances consists in being in the same key; whereas in dissonance, the notes, though struck at the same time, do not accord, but produce a grating on the ear that is extremely unpleasant. Let us, then, be grateful to the God of all love and mercy for the raptures that we enjoy from the impressions of sound pouring music through our souls; and raise one general song of joy, to celebrate his praises, that shall ascend into heaven, where the blessed angels of light will join in the full chorus of pure and heavenly harmony.