One of the most important lessons that can be impressed on the human mind, is that of self-knowledge and a just apprehension of what it is that we are competent to achieve. We can do much. We are capable of much knowledge and much virtue. We have patience, perseverance and subtlety. We can put forth considerable energies, and nerve ourselves to resist great obstacles and much suffering. Our ingenuity is various and considerable. We can form machines, and erect mighty structures. The invention of man for the ease of human life, and for procuring it a multitude of pleasures and accommodations, is truly astonishing. We can dissect the human frame, and anatomise the mind. We can study the scene of our social existence, and make extraordinary improvements in the administration of justice, and in securing to ourselves that germ of all our noblest virtues, civil and political liberty. We can study the earth, its strata, its soil, its animals, and its productions, "from the cedar that is in Lebanon, to the hyssop that springeth out of the wall." But man is not omnipotent. If he aspires to be worthy of honour, it is necessary that he should compute his powers, and what it is they are competent to achieve. The globe of earth, with "all that is therein," is our estate and our empire. Let us be content with that which we have. It were a pitiful thing to see so noble a creature struggling in a field, where it is impossible for him to distinguish himself, or to effect any thing real. There is no situation in which any one can appear more little and ludicrous, than when he engages in vain essays, and seeks to accomplish that, which a moment's sober thought would teach him was utterly hopeless. Even astronomy is to a certain degree our own. We can measure the course of the sun, and the orbits of the planets. We can calculate eclipses. We can number the stars, assign to them their places, and form them into what we call constellations. But, when we pretend to measure millions of miles in the heavens, and to make ourselves acquainted with the inhabitants of ten thousand times ten thousand worlds and the accommodations which the creator has provided for their comfort and felicity, we probably engage in something more fruitless and idle, than the pigmy who should undertake to bend the bow of Ulysses, or strut and perform the office of a warrior clad in the armour of Achilles.