sap in plants, and, on a larger scale, the air and the waters of the vast ocean circulate between the equator and the poles, while another species of circulation is created by the combined action of these two elements, which is exhibited in the various phenomena of clouds and rain, and of springs and rivers. It is to these that, as a preparation for considering the various processes of spring, I intend now to advert.

The earth is surrounded with an atmosphere of air, and into this another atmosphere, namely, that of water, in the form of steam or vapour, is introduced by evaporation. These two atmospheres are mingled together in such proportions, that the aerial part always greatly exceeds the aqueous,—the latter varying from about a hundredth, perhaps to a twentieth, part in weight of the former. Mr Whewell, in his Bridgewater Treatise, has very ingeniously shown, that the different laws by which these two fluids are regulated, though, on account of the complicated nature of their relations, their effects cannot always be distinctly traced, are yet such as can be demonstrated, in various particulars, to manifest the most remarkable proofs of wise arrangement, the one modifying and adjusting the other, so as to contribute to the subsistence of vegetable, and the enjoyment of animal, life. It is not consistent with our plan to go deeply into this subject; but the general view taken in the work alluded to, and by other writers on natural phenomena, may be mentioned in a few words. Were the atmosphere to consist entirely of aqueous vapour, the difference of heat in various latitudes, from the equator to the poles, would cause the vapour generated in the former regions to be more rare and elastic than that produced in the latter and intermediate climates; and this difference would create a constant circulation between these extreme points. The sky of the equatorial zone would be perpetually cloudless; but in all other latitudes we should, from the intermixing of the warm with the cold vapour, have " an uninterrupted shroud of clouds,

fogs, rains, and, near the poles, a continual fall of snow," "an excessive circulation of moisture, but no sunshine, and, probably, only minute changes in the intensity and appearances of one eternal drizzle or shower." This state of things would plainly be altogether unfavourable to vegetable and animal life; but the addition of an aerial atmosphere changes the condition, and by its agreement with the atmosphere of vapour in some particulars, and its disagreement, and even direct opposition, in others, so regulates and modifies the whole machinery of the weather, as to render it salubrious. "The alternations of fair weather and showers, appear to be much more favourable to vegetable and animal life, than any uniform course of weather could have been. To produce this variety, we have two antagonist forces, by the struggle of which such changes occur. Steam and air, two transparent and elastic fluids, expansible by heat, are in many respects and properties very like each other. Yet the same heat, similarly applied to the globe, produces, at the surface, currents of these fluids, tending in opposite directions. And these currents mix and balance, conspire and interfere, so that our trees and fields have alternately water and sunshine, our fruits and grain are successively developed and matured. Why should such laws of heat and elastic fluid so obtain, and be so combined? Is it not in order that they may be fit for such offices? There is here an arrangement, which no chance could have produced. The details of this apparatus may be beyond our power of tracing; its springs may be out of sight. Such circumstances do not make it the less a curious and beautiful contrivance. They need not prevent our recognizing the skill and benevolence which we can discover."

"

But besides the difference of heat and cold in different latitudes, there is a similar variation in the higher and lower strata of the atmosphere in the very same localities. The air becomes rapidly colder, as well as lighter, * Whewell's Bridgewater Treatise, p. 101.

in proportion to its height above the general surface of the earth; and this gives rise to other phenomena. The temperature of the air, as it increases in altitude, diminishes much more rapidly than that of vapour; and the result is, that the evaporated moisture has a constant tendency to ascend into the higher regions, which prevents the air at the surface from being saturated, and keeps up the evaporating process, while the warmer steam, mingling as it ascends with that which is already floating in equilibrium in the upper regions, occasions a precipitation, and hence the various phenomena of clouds, mist, and rain. These phenomena, again, are modified by the circumstances previously described ; and the various currents of warm and cold air, occasioned by many different causes, combined in numerous ways and in divers degrees, give rise to all the varieties of sunshine and cloud, moisture and drought, to which we apply the name of weather, and, by the due balance of which, the fertility of the different regions of the earth is secured.

Such is the general nature of the wonderful mechanism of the atmosphere, so wisely and so bountifully adapted to the organized existences produced by the soil. But there are other particulars also, which must not be forgotten. Among these, the provision by which the rain is made to fall softly on the earth, and to be diffused in due proportions over its surface, is peculiarly worthy of notice. When we think of the vast quantities of water continually floating over our heads, and at the same time reflect on the irregular and apparently capricious motions of the atmosphere, there seems, at first sight, to be much that is calculated to fill us with alarm. Could we suppose an intelligent being to drop on our globe, and to be made acquainted with just so much of the powers which regulate the antagonist forces of steam and air in our atmosphere, as philosophy has discovered, and no more, while he remained ignorant of the manner in which these powers practically operate,—a kind of knowledge which we learn from experience,-what would be

his conclusion? There is here, he would say, an amazing accumulation of moisture floating above the surface of the earth, and having a continual tendency, within certain bounds, to increase; but there are currents of air, sometimes breathing softly, sometimes driving furiously, sometimes expanding this moisture by its heat, sometimes suddenly precipitating it by its cold, sometimes dispersing it far and wide, sometimes strongly compressing it by pouring from opposite quarters. If all this is not regulated by some other principle than appears, by some over-ruling Intelligence, there must necessarily be the most destructive inequalities in its distribution over the surface of the earth. It will fall sheer down in some places in one unbroken sheet, so as to overwhelm whole continents with a sudden and fatal deluge, while, in other situations, an entire destitution of moisture will prove equally fatal to organic life. There is here no equilibrium, no compensating nor equalizing principle, so far as can be observed. The elements in action, and the forces employed, are so opposite and so powerful, that nothing but confusion and ruin can be the result.

Such is the legitimate conclusion which a rational being might form, without the aid of experience or the knowledge of a superintending Providence. But how different is the reality! The various phenomena of the weather, though irregular, and apparently capricious, when viewed from day to day, are yet preserved within salutary bounds, and wonderfully exhibit, in a series of weeks or months, a certain specific average, in a given locality, which is favourable for producing and nourishing the fruits of the earth. The cold or the heat, the sunshine or the gloom, may be longer protracted at one period than at another, but they are seldom carried to such an extreme as to prove injurious. The rain may sometimes fall in torrents, and occasional inundations may be the consequence; but such occurrences are rare exceptions from a well-conceived rule. The moisture is generally distilled from the clouds in gentle and fer

tilizing drops, at such seasons, and in such quantities, as are best calculated for cherishing the peculiar vegetation of the regions where it falls. All these circumstances are obviously adjusted to the qualities of the soil, and of the vegetable principle, so as to give scope to the powers of life inherent in nature, and to spread abundance and enjoyment over the earth.

Here, then, we have a new proof of designing wisdom and diffusive goodness,—the more admirable, as it is entirely in harmony with the character of the rest of the Creator's sublunary works. We do not find a system free from imperfection, and unmingled with evil; but we see tremendous and destructive forces controlled and regulated with consummate skill, so as to harmonize with the other powers and conditions of the physical world, while these, again, equally harmonize with the circumstances of the moral world,-thus forming one amazing but mysterious whole. And when we turn from this aspect of Nature, to that of Revelation, and compare them together, we here, above all, are presented with arguments, analogies, and accommodations, which at once astonish and delight, confound and satisfy, the inquiring mind.

FIRST WEEK-SATURDAY.

SPRINGS.

WATER is not only essential to the growth of plants, but to the subsistence of animal life. There is, however, this difference in the wants of these two orders of organized beings, that, whereas plants require only occasional supplies of this fluid, at considerable intervals, and are most luxuriant when, at particular seasons of the year, rainy weather is followed by uninterrupted sunshine for seve