The power of attraction and force of gravitation are the laws which govern the universe of matter. "The discovery of this law," says Prof. Olmsted, "made us acquainted with the hidden forces that move the great machinery of the universe. It furnished the key which unlocks the inner temple of Nature, and established the science of Astronomy upon a sure and firm basis. Thus we discover in Nature a tendency of every portion of matter toward some other. This tendency is called gravitation. The larger the body, the more powerful the attraction; and this attraction is always toward the centre. Hence, you may cast an object of weight into the air, and, when the impelling force you have given it ceases to force it upward, it falls in a direct line to the earth." So also may the Chinaman, placed on the opposite side of the globe, cast one as he deems upward, which is forcing it in an opposite direction from where you sent yours; yet, when his impelling force is lost, his too falls back to the earth, each falling toward the other. This is gravitation, produced by the power of attraction. Thus we now see this principle made plain to the simplest comprehension. _SUNS, STARS, PLANETS, &c._ We come, now, to the contemplation of that which is of far greater importance to us than all other planets, worlds, stars, and wonders in the siderial Heavens. This is the Sun, which warms and lights up our earth, and all the other planets within its sphere. Says Dr. Child, "There are not a few in this world who habitually receive God's blessings so much as a matter of course, that they are scarcely conscious of any active feeling of gratitude in regard to them. The very regularity and profusion with which these blessings are showered on all alike, seem to have the effect of deadening the sense of individual obligation. A general admission of thankfulness may occasionally be made at church or in the closet, but there is a want of that abiding consciousness of it, with which we ought to be imbued, as well as that frequent pondering upon details which, by illustrating the dependence of every creature upon God, causes the heart to swell with grateful adoration. Such thoughts never fail to improve our moral nature by bringing the truth home to us more and more that we are God's children. "It would be no easy task for a thankful mind to sum up all the blessings diffused over our planet by the Sun. It is the mainspring of animated Nature. Without its genial rays the present system of Earth's government could not endure, and life itself would soon disappear from the globe. To it we are indebted for light and warmth--the two stimulants of vital force--for our food and raiment; for our busy days and rest-bringing nights, for months and years, and happy alternations of seasons. Its rays, in short, are intertwined with all our wants and comforts; they gladden the eye and cheer the heart. Contemplating all these temporal blessings, the _Psalmist_ exclaims: