(as any little observation may easily manifest.) Therefore 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 inmediately 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.

PLUTARCH 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

out a sweet and comfortable air, pleasant dews, and gentle moisture, which might serve for refreshing and nourishment of the inhabitants and plants in that other world.

But since they have all things alike with us, as sea and land, and vaporous air encompassing both; I should rather therefore think, that nature there should use the same way of producing meteors as she doth with us; and not by a motion, (as Plutarch supposes) because she doth not love to vary from her usual operations without some extraordinary impediment, but still keeps her beaten path, unless she be driven thence.

One argument whereby I shall manifest this truth, may be taken from those new stars which have appeared in divers ages of the world, and by their paralax have been discerned to have been above the moon; such as was that in Cassiopeia, that in Sagittarius, with many others betwixt the planets. Hipparchus in his time took especial notice of such as these, and therefore fancied out such constellations in which to place the stars, shewing how many there were in every asterism; that so afterwards, posterity might know whether there were any new star produced, or any old one missing. Now the nature of these comets may probably manifest, that in this other world there are other meteors also; for these in all likelihood, are nothing else but such evaporations caused by the sun from the bodies of the planets. I shall prove this by shewing the improbabilities and inconveniences of any other opinion.

For the better pursuit of this, it is in the first place requisite, that I deal with our chief adversary, Cæsar la Galla, who doth most directly oppose that truth which is here to be proved. He endeavouring to confirm the incorruptibility of the heavens, and being there to satisfy the arguhich is taken from these comets; he answers it thus: Aut argumentum desumptum ex paralari, non est efficax, aut si est efficax, eorum instrumentorum usum decipere, vel ratione astri, vel medii, vel distantiæ, aut ergo

ment

*Plin. Nat. Hist. 1. 2. c. 26.

erat in suprema parte aeris, aut si in cælo, tum forsan factum erat ex reflexione radiorum Saturni & Jovis, qui tunc in conjunctione fuerant. "Either the argument from the "paralax is not efficacious, or if it be, yet the use of the "instruments might deceive, either in regard of the star,

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or the medium, or the distance, and so this comet might be in the upper regions of the air; or if it were " in the heavens, there it might be produced by the re"flection of the rays from Saturn and Jupiter, who were "then in conjunction." You see what shifts he is driven to, how he runs up and down to many starting holes that he may find some shelter; and instead of the strength of reason, he answers with a multitude of words, thinking (as) the proverb is) that he may use hail when he hath no thunder, Nihil turpius (saith Seneca *) dubio & incerto, pedem modo referente, modo producente. "What can "there be more unseemly in one that should be a fair disputant, than to be now here, now there, and so un"certain, that one cannot tell where to find him?" He thinks that there are not comets in the heavens, because there may be many other reasons of such appearances; but what he knows not: perhaps (he says +) that argument from the paralax is not sufficient; or if it be, then there may be some deceit in the observation. To this I may safely say, that he may justly be accounted a weak niathematician, who mistrusts the strength of this argument; not can he know much in astronomy, who understands not the paralax, which is a foundation of that science and I am sure that he is a timorous man, who dares not believe the frequent experience of his senses, or trust to a demonstration.

:

True indeed, I grant it is possible that the eye, the medium, and the distance, may all deceive the beholder, but I would have him shew which of all these was likely to cause an error in this observation? Merely to say they might be deceived, is no sufficient answer; for by this Į + Vide Galilæum Syst. Mundi, Colloq. 3.

* Epist. 95.

might confute the positions of all astronomers, and affirm the stars are hard by us, because it is possible they might be deceived in their observing distance. But I forbear any further reply: my opinion is of that treatise, that either it was set forth purposely to tempt a confutation, that he might see the opinion of Galilæus confirmed by others; or else it was invented with as much haste and negligence as it was printed, there being in it almost as many faults as lines.

Others think that these are not any new comets, but some ancient stars that were there before, which now shine with that unusual brightness, by reason of the interposition of such vapours, which do multiply their light; and so the alteration will be here only, and not in the heavens. Thus Aristotle thought the appearance of the milky way was produced: for he held that there were many little stars, which by their influence did constantly attract such a vapour towards that place of heaven, so that it always appeared white. Now by the same reason may a brighter vapour be the cause of these appear

ances.

But how probable soever this opinion may seem, yet if well considered, you shall find it to be altogether absurd and impossible: for,

1. These stars were never seen there before; and it is not likely that a vapour being hard by us, can so multiply that light which could not before be at all discerned.

2. This supposed vapour cannot be either contracted into a narrow compass, or dilated into a broad. 1. It could not be within a little space, for then that star would not appear with the same multiplied light to those in other climates. 2. It cannot be a dilated vapour, for then other stars which were discerned through the same vapour, would seem as big as that. This argument is the same in effect with that of the paralax, as you may see in this figure.