Imatges de pÓgina

were exhaled from it by the decomposition of its parts, and being collected together in the aerial regions, exhibited a luminous appearance by their rarefaction and dispersion throughout the atmosphere. We know that meteoric bodies, when suspended in the air, shed a light over a vast expanse; and in like manner, when the latent heat was abstracted from the solid bodies in which it subsisted, and formed itself into aerial vapour, surrounding the globe, it would illuminate the face of nature, in a manner somewhat similar to the sun. Thus there might be a species of atmospheric luminaries, which shone upon the earth, previous to the formation of the sun, which did not appear till a subsequent period. These, meeting together in a body, might be put into motion, and in the space of a day, enlighten every part of the surface of the globe, and thus make a separation of the light from the darkness, and a distinction betwixt day and night; besides facilitating the gradual developement of the congeries which still remained in a state of imperfect arrangement.

Since light is here particularly mentioned by the sacred historian, it may be necessary to give a definition of it. Light, in its natural state, is composed of very minute particles, emitted or reflected from every part of the surface of a luminous body, in right lines, in all directions, and with an unparalleled velocity. Its velocity is so extremely great, that it appears to be almost instantaneous; but by accurate observation it is found to move at the rate of two hundred thousand miles in a second of time, and proceeds from the sun to our earth, which is a distance of ninety-five millions, in about eight minutes. The rays of light darted from the sun to the earth, are of such intense heat, that a few of them collected in a prism of burning glass, burn the bodies on which they fall, although they have travelled such an immense distance. Even the heat of the sun in its ordinary operations on the surface of the globe, is found to vitrify the hardest bodies, and melt those that are soft and less adhesive. Its effects are perceptible by the organs of sight and touch. By means of light we are enabled to perceive forms and colours, and to feel also the sensation of heat. The utility of this natu



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ral agent is truly wonderful, and is here simply expressed in the words of the succeeding verse.

Ver. 4. And God saw the light that it was good :

The truth of this observation will appear by considering some of its most common properties, and the effects produced by it on the surface of the globe which we inhabit.

It is the grand medium, by which all the works of God are discovered, examined, and understood, as far as they can be known. By it all the planets are enlightened

. through the most remote regions of unlimited space. For this purpose, our sun is placed in the centre of the solar system, and transmits his rays to the earth and other heavenly bodies which revolve around him at different distances.—Were it not for this provision, the globe on which we live would be uninhabitable by reason of the cold which necessarily proceeds from an opaque and moist body such as it is. But, by the influence of his heat, the soil is invigorated with genial warmth, which nourishes and brings to maturity, the plants and herbs and fruits that overspread its surface, and thus supplies food for the wants of every living thing. By the heat of the sun, the seeds which we plant in our fields are vivified, and in due season produce an abundant crop for the sustenance of human life :-by the same heat the grass is quickened, and furnishes pasture for cattle and every beast that subsists on the soil, and by the same heat we and every creature are preserved in that due degree of temperature, by which the functions of animal life are sustained in their vigour. By its kindly influence, light is supplied to enable us to execute our daily labours, and perform every office required of us as active beings. By the light of the sun, “ man goes forth to his work and his labour till the evening,” and his eye is gladdened by the cheering aspect of the day. By his light, we can extend our view over the fair face of nature, and discover the innumerable objects which present themselves to view, we can admire their beauty, study their properties, and apply them to our use. But if denied this medium of perception, how globmy and cheerless would be our condition! We would live in the

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world, without being capable of enjoying the pleasurės arising from our sight, or transacting any operation which is necessary for ministering to our wants or our comforts. Whereas, by this astonishing provision, we can go out and come in, and act our part in the world under the constant illumination of that celestial luminary which lightens every man that liveth in the world.

It is worthy of remark, that the wisdom of God is conspicuously manifested in placing the sun, which is the source of light and heat, at such a due distance from our globe, that we receive all his beneficial influences, without incurring any of their inconveniences. Accordingly it is evident, that had we been much nearer this orb of day, the world and its inhabitants would have been parched with heat; the waters would have been condensed into vapours and dried up; vegetation would have ceased, and all things on the surface have been consumed. On the contrary, if we had been placed at a greater distance, the sun's heat would have been so much diminished, that the earth and its inhabitants would been frozen up, and, instead of being a pleasant residence for human beings and other animals, it would have been a dreary wilderness, an uninhabitable desert.-By the position of the earth, also, the inclination of its axis to its orbit, and its diurnal and periodic revolutions, all parts of our globe receive a due proportion of light and heat, and all its regions are successively visited with the genial influence of the solar rays. Thus, if we consider the wise provision afforded by that agent, the properties of which have been now described, we will concur in the sentiment expressed in the verse, that “light is good," and join with David in saying, “great and marvellous are thy works, Lord God Almighty! in wisdom hast thou made them all.”—Another circumstance respecting the nature of our terraqueous globe, is that interchange of light and darkness which constantly succeed each other at periodical measures of duration. Thus it is said, that “ God divided the light from the darkness." These words refer, by anticipation, to the rotation of the earth round its axis, once in twenty-four hours, which is the cause of day and night, by bringing the different parts of the surface of the earth

within the influence of the solar rays; and it is probable that at the instant here spoken of, the Almighty Creator imparted that rotatory motion to the new formed sphere, by which such a phaenomenon was effected.

It is well known to every one, who is acquainted with the first principles of astronomy, that the earth revolves round the sun in an elliptical orbit, and that she completes this revolution in the space of a year.-During the course, of her progress, the earth is removed farther from the sun at one time, and approaches nearer at another, and this circumstance, together with the inclination of her axis either towards, or from that luminary, occasions the vicissitudes of the seasons.-Besides this annual rotation, the earth performs a daily revolution round her own axis, by which one half of her surface is illuminated during the day, and the other half is left in darkness during the night. You may easily comprehend in what manner these changes are effected, by holding any round body near a candle, and you will perceive that its light will be reflected on the part that is turned towards it, while the opposite part will be obscured for want of light. The former case may represent the mode in which the sun enlightens the world in that period of time which we call day, and the latter, the cause by which darkness ensues during the night; and if the same body be moved round, it will exhibit the diurnal rotation of the earth, by which all parts of it are successively illuminated or obscured, and the rising or setting of the sun accounted for on the simplest principles. This daily motion of the earth round its axis, is the most excellent provision for supplying an equal degree of light and heat to the globe which we inhabit. For if it remained immovable, that side only on which the sun shone would receive the benefit of his rays, while the other would be left in perpetual darkness, and become useless as a habitation to living beings. Whereas, by its present position and revolutionary motion, day and night succeed each other at certain intervals, and minister to the necessities of nature, and the comfort of every living thing. While the light of the day enables us to pursue Our employments, the darkness of the night is wisely or

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dained as the season for the cessation of labour, and repairing our wearied bodies by the enjoyment of sleep. While the sun also has been shedding his heat for fertilizing the face of nature throughout the day, the earth is refreshed by the cooling temperature which ensues during night; so that in the system of nature as well as the animal economy, it may be truly asserted, that “all things are fearfully and wonderfully made.”

Ver. 5. And God called the light day, and the darkness he called night: and the evening and the morning were the first day.

This measure of duration is distinguished by two different names, natural and artificial. The natural day is that space of time, during which it continues to be light, or the period which elapses betwixt the rising and setting of the sun.

The length or shortness of the day varies in summer and winter, because in the former season, the inclination of the earth's axis is more towards the sun, than in the latter, and the variation which it is constantly undergoing in its motion through the ecliptic, produces the difference of day and night which we experience in the course of a year. Hence the natural day begins when the sun appears above our horizon in the east, and continues as long as he is visible, till he sets below our horizon in the west,

The artificial day is that portion of time which the earth requires to revolve round her own axis, and thereby receive the benefit of his light and heat throughout the whole of her surface. This is completed in twenty-four hours, and therefore includes the night when the sun is removed from our view, and enlightening other regions of the globe. This last measure of duration is that by which time is computed; and hence a week which consists of seven days, comprehends both day and night during that period; and a year contains three hundred and sixtyfive days and nights, according to the present mode of calculation.-Days have acquired a variety of names, among different nations of the world ; and those by which they are designated in this country, have been derived

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