place of refuge; it was enough that, like the light of a dark lantern, it could send its rays in any one direction through the almost impervious atmosphere around.

It was in consequence of this condition of society that the knowledge of the earth's sphericity remained for so long a period unimproved. It was a thousand years after the fall of Rome that the greatest of geographical discoveries was founded on the astronomical discovery that the earth was a sphere. It was when Copernicus was a young man, but before the publication of his works, that Columbus, by the direct conclusions of scientific reasoning, discovered America. It is true that Columbus had the compass (another discovery in navigation due to astronomy), but it was not the compass which induced the reasoning, in the pursuit of which he reached the shores of the western continent.

He argued, that the earth being a sphere, by sailing continually in one direction, he must eventually circumnavigate it. He argued also, that as the known land occupied but a small portion of the known surface of the globe, the equilibrium of matter, and the purposes for which the earth was formed, required there should be other lands in the depths of the Western Ocean. This was as legitimate a conclusion from the astronomical discovery and demonstration that the earth was a sphere, as any corollary is from any theorem.

Thus there is a complete sequence of ideas and

conclusions from the first demonstration deduced from astronomical observations that the earth was a globe, down to the final discovery of a new continent in the Atlantic Ocean. Who can estimate the value and the vast moral consequences of this continent, thus discovered, to the whole future life, dignity, and destiny of the human race!

To the eye of science, of Christian civilization, and of progressive humanity, it has emerged from the bosom of the seas perfectly and absolutely a new world; to the advancing generation of men in Europe and Asia, crowded in dense masses upon the old-settled portions of the earth, it acts as a new creation, inviting them to new conquests in the field of labor, to new investigations by the human mind, and to fresh hopes in the pursuit of happiness.

ASTRONOMY DETERMINES PLACE ON THE EARTH.

Astronomy has not only discovered new continents, but it has determined the relations of each spot on the earth to every other spot. In one word, it has enabled us to determine where any one place is, relatively to the whole surface of the globe. How, without such knowledge, could the position of any town or place ever be described? The lines of latitude and longitude are the only means by which the locality of any spot on earth can be determined with any accuracy: they are the true basis of all other subdivisions. These lines are purely astronomical;

they determine place by mathematical conclusions drawn from astronomical observations. Thus, a point is fixed relatively only by the intersection of two lines: if we knew the position of one of these lines, and did not know that of the other, we should know that the point to be ascertained was in the known line, but where in that line we should not know. That point, however, which is at the intersection of two lines is palpably fixed, because it could not move without leaving that intersection. If one of these lines, then, be a line of latitude, and the other a line of longitude, it fixes the relative position of that place on the surface of the earth. This is what gives certainty to place on our maps, and gives a corre sponding certainty to it in our minds.

To do this so that the idea of that place should forever remain fixed with accuracy in our descriptions of the earth, and not change with changing generations, was necessary to the truth of history and the durability of human records. It is done by taking as the basis of one of these measures, a line which is permanently fixed on the earth, by the very mechanism of the celestial universe. This line is the equator, or the intersection of the earth's surface with a plane, passing through its centre perpendicular to the axis of revolution. The revolution of the earth on its axis, then, determines the equator, and the distance of a place from the equator gives us the latitude.

The longitude is dependent on the same principles; it is the distance measured on the earth's surface

between two planes passing through the axis of the earth. These two planes, then, one passing through the axis of the earth, and the other perpendicular to it, are both dependent on that axis of revolution for existence. Latitude is measured from one, and longitude from the other: these two determine place. Thus the exact relation, distance, and geographical position of every spot on earth is fixed, so that it will remain durably impressed on the pages of history, the lines of a chart, and the memory of the human intellect. This result is deduced from the axis of the

earth.

This again depends on the revolutions of the earth; .and these revolutions are observed and accurately demonstrated by astronomical science.

Nor is this all. The longitude, or difference between two meridians, is ascertained by the most vigilant and minute observation of celestial phenomena. To do this ccurately, it is necessary to observe the eclipses of the moon, the eclipses of Jupiter's satellites, or the transit of some planet.

Thus does astronomy minister directly to one of the most common and useful branches of knowledge ; thus does it determine distance and locality; thus does it make clear and beautiful charts of lands, seas, and islands, which, without it, would have existed in our minds only in a wild waste of confusion. No accurate measurement of lands, no true relations of distances, no correct charts exist, which owe not their accuracy and their being to those celestial orbs

whose rays do not more surely descend upon matter, than does their mechanism give knowledge, suggestion, and aliment to the mind of the observer.

ASTRONOMY DETERMINES THE MAGNITUDE OF THE

GLOBE.

Again: astronomy not only determines the relation of places to one another, but it has ascertained the exact magnitude of the globe itself—the limit of space assigned to mortal man in his abode on earth. By successive measurements of a degree on the surface of the earth, and its relation to the corresponding one of a meridian-measurements made by Picard, and various other astronomers-the precise diameter of the earth was calculated, and the quantity of its surface. Nor was this all: by the calculations of various arcs of circles on the earth, it was revealed that our globe was not precisely a sphere, but was what, in the language of mathematics, is called an oblate spheroid; that is, a sphere flattened at the poles.

This again gave rise to deep investigations as to the laws of gravitation, by which it is proved that the attraction is less at the equator than the poles, and that the earth could not be a homogeneous mass. By a succession of profound calculations, based on astronomical observations, was thus discovered and proved the laws which govern the irregularity of a sphere in motion, the magnitude of its surface, and the density of its mass.