NICOLAUS COPERNICUS ON THE REVOLUTIONS

BOOK ONE.

That the universe is spherical. Chapter I.

[An ornate initial letter P, decorated with the figure of a scholar at his desk]
IN THE BEGINNING we must observe that the universe original: "mundus"; in this context, Copernicus refers to the entire cosmos or the heavens. is spherical, either because that form is the most perfect of all, needing no joints and being a complete whole; or because it is the most capacious of shapes, which is most fitting for that which is to contain and preserve all things; or even because the most finished parts of the universe—I mean the Sun, the Moon, and the stars—are observed to have such a shape; or because all things seek to be bounded by this form, which is apparent in drops of water and other liquid bodies when they desire to be bounded by themselves. Therefore, no one should doubt that such a form has been assigned to the celestial bodies.

That the earth is also spherical. Chapter II.

[An ornate initial letter T, decorated with a landscape showing hills and trees]
That the earth is also spherical, since it presses upon its center from every side. Although a perfect sphere is not immediately apparent because of such great height of mountains and the depth of valleys, these nevertheless do not significantly alter the overall roundness of the earth. This is manifest in this way: for to those traveling anywhere toward the North, that pole of the daily revolution is gradually raised, while the other pole sinks by the same amount in the opposite direction; and many stars around the North are seen not to set, while in the South some stars no longer rise. Thus Italy does not see Canopus, which is visible in Egypt. And Italy sees the last star of the River the constellation Eridanus, which our region of a colder climate Copernicus refers here to his home in Warmia, Poland/Prussia. does not know. Conversely, for those traveling South, those stars are raised, while those which are high for us sink down. Meanwhile, the inclinations of the poles have everywhere the same ratio to the distances measured on the earth, which [occurs...]