ceives light from a proportionable part of the earth which shines upon it, as you may plainly perceive by the figure.

You see then that agreement and similitude which there is betwixt our earth and the moon. Now the greatest difference which makes them unlike, is this, that the moon enlightens our earth round about, whereas our earth gives light only to that hemisphere of the moon which is visible unto us; as may be certainly gathered from the constant appearance of the same spots, which could not thus come to pass, if the moon had such a diurnal motion about its own axis as perhaps our earth hath. And though some suppose her to move in an epicycle, yet this doth not so turn her body round, that we may discern both hemispheres; for according to that hypothesis (say they) the motion of her eccentric doth turn her face towards us, as much as the other doth from us.

But now, if any question what they do for a moon, who live in the upper part of her body? I answer, The solving of this, is the most uncertain and difficult thing that I know of, concerning this whole matter. But yet unto me this seems a probable conjecture.

That the upper hemisphere of the moon doth receive a sufficient light from those planets about it; and amongst these, Venus (it may be) bestows a more especial brightness, since Galilæus hath plainly discerned that she suffers the saine increases and decreases, as the moon hath; and it is probable that this may be perceived there, without the help of a glass, because they are far nearer it than we. When Venus (saith Keplar) lics down in the perige or lower part of her supposed epicycle, then is she in conjunction with her husband the sun; from whom, after she hath departed for the space of ten months, she gets plenum uterum, and is in the full.

But you will reply, though Venus may bestow some light when she is over the moon, and in conjunction, yet being in opposition, she is not visible to them, and what shall they then do for light?

I answer; then they have none; nor doth this make so great a difference betwixt those two hemispheres, as there is with us betwixt the places under the poles and the line. And besides, it is considerable that there are two kind of planets.

1. Primary; such whose proper circle do encompass the body of the Sun, whereof there are six; Saturn, Jupiter, Mars, Ceres or the Earth, Venus, Mercury. As

in the frontispicce.

2. Secondary; such whose proper circles are not about the sun, but some of the other primary planets. Thus are there two about Saturn, four about Jupiter, and thus likewise does the moon encompass our earth. Now it is probable that these lesser secondary planets, are not so accommodated with all conveniencies of habitation, as the others that are more principal.

But it may seem a very difficult thing to conceive, how so gross and dark a body as our earth, should yield such a clear light as proceeds from the moon; and therefore the Cardinal de Cusa* (who thinks every star to be a several world) is of opinion, that the light of the sun is not able to make them appear so bright; but the reason of their shining is, because we behold them at a great distance through their regions of fire, which do set a shining lustre. upon those bodies that of themselves are dark. Unde si quis esset extra regionem ignis, terra ista in circumferentia sua regionis per medium ignis lucida stella appareret. "So that if a man were beyond the region of fire, this "earth would appear through that as a bright star." But if this were the only reason, then would the moon be freed from such increases and decreases, as she is now liable unto.

Keplar thinks that our earth receives that light whereby it shines, from the sun; but this (saith he) is not such an intended clear brightness as the moon is capable of, and therefore he guesses that the earth there is of a more

De doct. ig. 1. 2. c. 12,

choaky soil, like the isle of Crete, and so is better able to reflect a stronger light; whereas our earth must supply this intention with the quantity of its body. But this I conceive to be a needless conjecture, since our earth (if all things were well considered) will be found able enough to reflect as great a light. For,

1. Consider its opacity; if you mark these sublunary things, you shall perceive that amongst them, those that are most perspicuous, are not so well able to reverberate the sun-beams, as the thicker bodies. The rays pass singly through a diaphanous matter, but in an opacous substance they are doubled in their return, and multiplied by reflection. Now if the moon and the other planets can shine so clearly by beating back the sun-beams, why may not the earth also shine as well, which agrees with them in the cause of this brightness, their opacity?

2. Consider what a clear light we may discern reflected from the earth in the midst of summer; and withal, conceive how much greater that must be which is under the line, where the rays are more directly and strongly rever berated.

3. It is considerable, that though the moon does in the night-time seem to be of so clear a brightness, yet when we look upon it in the day, it appears like some little whitish cloud: not but that at both times, she is of an equal light in herself. The reason of this difference is, because in the night we look upon it through a dark and obscure medium, there being no other enlightened body, whose brightness may abate from this: whereas in the day-time, the whole heavens round about it are of an equal clearness, and so make it to appear with a weaker light. Now because we cannot see how the enlightened parts of our earth do look in the night, therefore in com paring it with the moon, we must not consider her, as she is beheld through the advantage of a dark medium, but as she seems in the day-time. Now in any clear sunshine day, our earth does appear as bright as the moon, which at the same time does seem like some duskish cloud

(as any little observation may easily manifest.) There-, fore we need not doubt but that the earth is as well able to give light as the moon. To this it may be added, that those very clouds, which in the day-time seem to be of an equal light to the moon, do in the evening become as dark as our earth; and as for those of them which are looked upon at any great distance, they are often mistaken for the mountains.

4. It is considerable, that though the moon seem to be of so great a brightness in the night, by reason of its nearness unto those several shadows which it casts, yet is it of itself weaker than that part of twilight, which usually we have for half an hour after sun-set, because we cannot till after that time discern any shadow to be made by it.

5. Consider the great distance at which we behold the planets, for this must needs add much to their shining; and therefore Cusanus (in the above-cited place) thinks that if a man were in the sun, that planet would not appear so bright to him, as now it doth to us, because then his eye could discern but little; whereas here, we may comprehend the beams as they are contracted in a narrow body. Keplar beholding the earth from a high mountain, when it was enlightened by the sun, confesses that it appeared unto him of an incredible brightness, whereas then he could only see some small parts of it; but how much brighter would it have appeared, if he might in a direct line behold the whole globe of earth and these rays gathered together? So that if we consider that great light which the earth receives from the sun in the summer, and then suppose we were in the moon, where we might see the whole earth hanging in those vast spaces, where there is nothing to terminate the sight, but those beams which are there contracted into a little compass; I say, if we do well consider this, we may easily conceive that our earth appears as bright to those other inhabitants in the moon, as theirs doth to us.

But here it may be objected, that with us for many days in the year, the heavens are so overclouded, that we

cannot see the sun at all; and for the most part, in our brightest days, there are many scattered clouds which shade the earth in sundry places: so that in this respect, it must needs be unlike the moon, and will not be able to yield so clear, unintermitted a light, as it receives from that planet.

To this I answer.

1. As for those lesser brighter clouds, which for the most part are scattered up and down in the clearest days, these can be no reason why our earth should be of a darker appearance, because these clouds being near unto the earth, and so not distinguishable at so great a distance from it]; and likewise being illuminated on their back parts by the sun that shines upon them, must seem as bright to those in the moon, as if the beams were immediately reflected from our earth.

2. When these clouds that are interposed, are of any large extension, or great opacity, as it is in extraordinary lasting and great rains, then there must be some discernible alteration in the light of our earth: but yet this does not make it to differ from the moon, since it is so also with that planet, as is shewed in the latter part of the next chapter.

PROP. XII.

That it is probable there may be such meteors belonging to that world in the Moon, as there are with us.

LUTARCH discussing on this point, affirms that it is not necessary there should be the same means of growth and fructifying in both these worlds, since nature might in her policy find out more ways than one how to bring about the same effect. But however, he thinks it is probable that the moon herself sendeth forth warm winds; and by the swiftness of her motion, there should breathe