When a mind of great and acknowledged power first directs its energies to the study of the material universe, no indications of order attract his notice, and no proofs of design call forth his admiration. In the starry firmament he sees no bodies of stupendous magnitude, and no distances of immeasurable span. The two great luminaries appear vastly inferior in magnitude to many objects around him, and the greatest distances in the heavens seem even inferior to those which his own eye can embrace on the surface of the earth. The planets, when observed with care, are seen to have a motion among the fixed stars, and to vary in their magnitude and distances, but these changes appear to follow no law. Sometimes they move to the east, sometimes to the west, sometimes towards the north, and sometimes towards the south, and at other times they are absolutely stationary. No system, in short, appears, and no general law seems to direct their motions. By the observations and inquiries of astronomers, however, during successive ages, a regular system has been recognised in this chaos of moving bodies, and the magnitudes, distances, and revolutions of every planet which composes it has been determined with the most extraordinary accuracy. Minds fitted and prepared for this species of inquiry are capable of understanding the great variety of evidence by which the truth of the planetary system is established; but thousands of individuals who are even distinguished in other branches of knowledge are incapable of such researches, and view with a skeptical eye the great and irrefragable truths of astronomy. That the sun is stationary in the centre of our system,—that the earth moves round the sun, and round its own axis,—that the earth is 8000 miles in diameter, and the sun _one hundred and ten_ times as large,—that the earth’s orbit is 190 millions of miles in breadth,—and that if this immense space were filled with light, it would appear only like a luminous point at the nearest fixed star,—are positions absolutely unintelligible and incredible to all who have not carefully studied the subject. To millions of our species, then, the great book of nature is absolutely sealed, though it is in the power of all to unfold its pages, and to peruse those glowing passages which proclaim the power and wisdom of its mighty Author.