478

ment

may

be employed in rejecting or altering hypoth eses. Having therefore now opened the way, I will make a few general observations on the motions themselves. I have said that there are four kinds of greater motions in the heavens. Motion in the depth of heaven, upward or downward; motion through the latitude of the zodiac, deviating to south and north; motion in the direction of the zodiac, quick, slow, progressive, retrograde, and stationary; and motion of elongation from the sun. And let no one object that this second motion of latitude, or the dragons, might have been referred to that great cosmical motion, being an alternate inclination towards north and south; inasmuch as these spirals move in like manner from tropic to tropic; only that the cosmical motion is spiral simply, whereas the other is likewise sinuous and with much smaller intervals. For this has not escaped me. But the fact is, that the constant and perpetual motion of the sun in the ecliptic without latitude and dragons, which sun nevertheless has a common motion with the other planets in respect of spirals between the tropics, forbids me to agree with this opinion. We must therefore seek other sources both of this and of the three other motions. Such are the ideas with regard to the celestial motions which seem to me to have least inconvenience. Let us see then what they deny and what they affirm. They deny that the earth revolves. They deny that there are two motions in the heavenly bodies, one being from west to east; and affirm a difference in speed, one outstripping and leaving the other behind. They deny an oblique circle with a different position of its poles; and affirm spirals. They deny a separate primum mobile, and carriage by force; and affirm a

cosmical consent as the common bond of the system. They affirm that the diurnal motion is found not in the heaven only, but also in the air, water, and even the exterior of the earth, in respect of its verticity. They affirm that this cosmical motion of flowing and rolling. in fluids, becomes verticity and direction in solids, until it passes into pure immobility. They deny that the stars are fixed like knots in a board. They deny that eccentrics, epicycles, and such structures are real. They affirm that the magnetic motion, or that which brings bodies together, is active in the stars, whereby fire evokes and raises fire. They affirm that in the planetary heavens the bodies of the planets move and revolve with greater velocity than the rest of the heaven in which they are situated, which does indeed revolve but more slowly. They affirm that from this inequality come the fluctuations, waves, and reciprocations of the planetary ether, and from them a variety of motions. They affirm a necessity in the planets of revolving faster and slower, according as they are situated high or low in the heaven, and that by consent of the universe. But at the same time they affirm a dislike in the planets of preternatural velocity as well of the greater as of the lesser circle. They affirm a tendency to follow the sun, by reason of neediness of nature, in the weaker fires of Venus and Mercury; the rather, because Galileo has discovered certain small wandering stars attendant upon Jupiter. These then are the things I see, standing as I do on the threshold of natural history and philosophy; and it may be that the

1 Motum diurnum inveniri non in cælo, sed et in aëre, aquis, etiam extimis terræ, quoad verticitatem. So the sentence stands in the original. But it seems that tantum or some equivalent word has dropped out. — J. S.

480

TRANSLATION OF THE THEMA COLI."

deeper any man has gone into natural history the more he will approve them. Nevertheless I repeat once more that I do not mean to bind myself to these ; for in them as in other things I am certain of my way, but not certain of my position. Meanwhile, I have introduced them by way of interlude, lest it be thought that it is from vacillation of judgment or inability to affirm that I prefer negative questions. I will preserve therefore, even as the heavenly bodies themselves do (since it is of them I am discoursing), a variable constancy.

INDEX

TO THE

PHILOSOPHICAL WORKS.

Note. The parts of the Index printed in Italic refer to the Editors' Prefaces and Notes.