were the instruments of this mighty change, sound philosophy would itself lead to the conclusion that there was a period in the formation of the world, when "God said, Let the waters under the heavens be gathered together unto one place, and let the dry land appear; and it was so."

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5. A similar adaptation to beneficial purposes is found in the atmosphere which envelopes the earth. It is almost superfluous to dwell upon its obvious uses. It is indispensably necessary for sustaining animal and vegetable life. It supports and conveys the clouds and vapours, which descend upon the earth in rain and dew. It diffuses equably the light of the sun; so that even those parts of objects, which are not directly illuminated, are visible: it renders the change from day to night gradual; accompanied with circumstances of the greatest beauty; and in some parts of the earth it prolongs the duration of the light of day, after the sun has disappeared, in a manner highly conducive to the comfort of the inhabitants. It is the vehicle by which various odours are transmitted to the sense, and sounds are conveyed to the ear, susceptible of such delicate modulation as to be the readiest signs of ideas, and to afford a source of high grati

Gen i. 9.

fication, by their pleasing succession or harmonious combination.

But there are other less obvious, but equally important properties in the air which we breathe; properties which indicate selection and design. Air is an elastic fluid, possessing weight, and capable of being contracted or expanded by a variation in heat or pressure. The peculiar degree of density, which it is found to possess at the surface of the earth, arises from the relation between the attractive force of gravity, and the repulsive force of the particles of which the atmosphere is composed. And this density could not be materially altered without occasioning much inconvenience.

If the density of the air were greatly increased, the light which we receive from the heavenly bodies would be sensibly diminished; and the effects of storms and of all agitations of the atmosphere would be augmented. Consequences still more hurtful would follow from a diminution of the density of the atmosphere, even if the respiration of animals could be carried on.

In the passage of the solar rays through the atmosphere, heat is produced. The air therefore, possessing a sufficient density, is necessary to preserve the temperature of the earth at that degree which is found most

beneficial to its various inhabitants.

But there

is still another consequence connected with the density and therefore the pressure of the atmosphere. The air is necessary to keep down the sea. Were the atmospheric pressure removed, or greatly diminished, there would be but little, if any, intermediate state of the waters of the ocean between the solid and aeriform state. A far less degree of heat than is now frequently experienced would dissipate all the waters upon the face of the earth.

So connected are all the phenomena of the natural world. So many things conspire to render this globe a residence for living animals, and to make it subservient to their convenience.

6. The proportion which is found between sea and land upon the surface of the earth is another instance of beneficial adaptation to the use of man, and of other creatures. And it is, besides, a benefit arising from a cause which, at first sight, might appear calculated to produce great inconvenience. We might imagine that the interposition of vast oceans between different lands would have been an insurmountable obstacle to any intercourse. Whereas it affords the most commodious means of effecting it. Again, since a great portion of the surface of the earth is covered by sea, the

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space adapted to terrestrial animals is proportionally limited. We might perhaps have imagined that a greater surface of land capable of producing the fruits of the earth, would have enabled our planet to support a greater number of living creatures. But besides the consideration of the numerous beings in a state of life and enjoyment, which the ocean contains, not only near its surface, as the earth does, but probably to vast depths, it is easy to perceive that the quantity of sea is not greater than is requisite to secure the fertility of the earth. The ocean is a mighty reservoir: and its contents are in a state of continual circulation. By the wonderful, and hitherto inimitable, property of natural evaporation, which from a salt ocean extracts the most pure and limpid water, the clouds are formed in the atmosphere. These are driven by the winds over the most extensive continents. The rains fall upon the fruits of the earth, and essentially contribute to bring them to maturity. They supply the springs and rivers, which, after having adorned and enriched the earth in their course, return to the ocean from which they were derived. We are not, perhaps, competent to form a just estimate of the precise proportion between sea and land, which would best secure these various purposes. But we are able to see that the

existing proportion serves them all: that a material alteration in that proportion would be attended with much inconvenience, even if it did not prove destructive.

7. The magnitude of the tides, caused by the attraction of the sun and moon upon the waters of the ocean, is another circumstance which deserves particular notice, as affording a strong presumption of design.

The tides, as they at present exist, are eminently beneficial. Perhaps we cannot even conceive any more perfect system of the same nature. This periodical undulation, arising not from any superficial cause, such as the agitation of the winds, disturbs the ocean to its greatest depths, and effectually prevents any stagnation of its waters. Upon the coasts of the ocean, in narrow seas, and especially in rivers, it produces a current which is of the greatest convenience to navigation. By its aid, the mariner is frequently able to direct his course, with nearly as much certainty as if the winds of heaven were, for several hours, invariably favourable to his progress, and again, for a corresponding period, propitious to his return. In order to produce these beneficial effects, many independent parts must be arranged, each within certain small limits. The tides are caused by the gravitation of the sun, the moon, and the earth towards