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flutterings of a microscopic animalcule; a power which astonishes and confounds the imagination, which sets at defiance human calculations, but which conveys to the mind a most impressive idea of the grandeur of the Divine Being, and of the magnificence of that universe which his hands have formed 1

It is not merely in the scenes of the visible world that the attributes of Deity are conspicuously displayed. Even in the invisible regions of creation, which are impalpable to the organs of human vision, the perfections of the Eternal Mind are no less apparent to the philosophic and Christian inquirer, than in those external scenes of beauty and magnificence which arrest the attention of every spectator. Could we descend to the central regions of our globe, and contemplate the processes which are going on in those unexplored and unexplorable recesses; could we penetrate into the depths of the ocean, and survey the multiplicity of objects which lie concealed in its unfathomable caverns; could we ascend on the wings of the wind with the vapours which rise from its surface, and contemplate all the regions and transformations through which they pass, till they again descend in refreshing rains on the mountains and vales; could we wing our flight beyond the denser regions of the atmosphere into those places where fire-balls and shooting-stars have their origin, and where the aurora borealis displays its fantastic coruscations; could we ascend to the ethereal spaces which intervene between us and the celestial bodies, and investigate those apparently empty regions which surround the atmospheres of all the planets; or, could we penetrate into the chemical processes and changes which are incessantly going on among the invisible atoms of matter, in the union and disunion of the different gases, in the various modifications of crystallization, in the circulation of the sap and juices in the minutest flowers, and in the internal vessels of microscopic animalcules; we should, doubtless, behold the operations of a Wisdom and Intelligence no less admirable and astonishing than what is displayed in the visible scenes of nature which are obvious to every eye.

Of those invisible regions of nature now alluded to, the Atmosphere is one in which we are particularly interested, and which exhibits a striking scene of Divine wisdom and beneficence.

The term atmosphere may be defined to be "that body of air, vapours, electric fluid, and other substances which surrounds the earth to a certain height." This mass of fluid matter gravitates towards the earth, presses upon its surface with a certain force, revolves with it in its diurnal rotation, and is carried along with it in its course round the sun, at the rate of sixtyeight thousand miles an hour. This fluid mass is invisible to the corporeal organs; and hence, the great body of mankind are apt to imagine that the regions around us in which the birds fly, and the clouds move, are nothing else than empty space; and, were it not that they sometimes hear its sound in the breeze, and feel its effects in the whirlwind and the storm, they would be disposed to deny that such a thing as the atmosphere had an existence. There is, however, no appendage to our globe which is so essentially requisite to the comfort, and even to the very existence of animated beings; forf were the earth and the ocean, the springs and the rivers, to remain as they now are, but were the hand of Omnipotence to detach from our globe the atmosphere with which it is now environed, it is absolutely certain that, in a few minutes, and after a few sighs and groans, all the eight hundred millions of men that now people the earth, and all the other animated beings that traverse the air, the waters, and the land, would sink into the slumbers of death, and disappear for ever from the living world.

In elucidating this subject, the observations that will be made may be arranged under the following heads:— I. To prove that air exists, and that it is a

material substance. Ii. To consider its weight or gravity, and the

force with which it presses on all bodies

on the surface of the earth. in. To exhibit several facts which the pressure

of the atmosphere tends to illustrate. IV. To illustrate the elasticity of the air, and

the effects it produces. V. To offer some considerations for illustrating

the height of the atmosphere, or its elevation above the surface of the earth.

vi. To illustrate its composition; or, the chemical principles of which common atmospherical air is composed.

vii. To illustrate its beneficial effects in the system of nature.

vm. To exhibit the evidences which its constitution affords of the wisdom and benevolence of the Creator.

CHAPTER I.

Air is a material substance.

The first inquiry, then, is, What is that air, of the importance of which we hear so much asserted? We see nothing, it may be said— we feel nothing. We feel ourselves at liberty to move about without any let or hindrance. Whence, then, the assertion that we are surrounded by a substance called air? A few facts and illustrations only will be sufficient to elucidate this position.

1. If we take a rod, and make it pass rapidly through what appears empty space, we shalL hear a sound and feel a slight resistance, as if something had intervened to prevent the motion of the rod.

2. If we take a large fan, or an umbrella, when fully stretched, and push it forcibly from us, we shall feel a very considerable resistance, and a person opposite will feel a certain impression made upon his face, as if some substance had come in contact with it. Were we to take a very large umbrella—say from twelve to fifteen feet diameter—and stand on the top of a high

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