So in this world also there may be some such body, though wee cannot discerne it, because the Moone is alwaies in a streight line, betwixt our eye and that. Nor is it altogether unlikely that there should bee more moones to one Orbe, because _Jupiter_ also is observed to have foure such bodies that move round about him. But it may seeme a very difficult thing to conceive, how so grosse and darke a body as our earth, should yeeld such cleare light as proceedes from the Moone, and therefore the Cardinall _de Cusa_[1] (who thinkes every Starre to be a severall world) is of opinion that the light of the Sunne is not able to make them appeare so bright, but the reason of their shining is, because wee behold them at a great distance through their regions of fire which doe set a shining lustre upon those bodies that of themselves are darke. _Vnde si quis esset extra regionem ignis, terra ista in circumferentia suæ regionis per medium ignis lucida stella appareret._ “So that if man were beyond the region of fire, this earth would appear through that as a bright Starre.” But if this were the onely reason then would the Moone bee freed from such increases and decreases as shee is now lyable unto. [Sidenote 1: _De doct. ig. l. 2. c. 12._] _Keplar_ thinkes that our earth receives that light whereby it shines from the Sunne, but this (saith he) is not such an intended cleare brightnesse as the Moone is capable of, and therefore hee guesses, that the earth there is of a more chokie soyle like the Ile of _Creete_, 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 needlesse 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 marke these sublunary things, you shall perceive that amongst them, those that are most perspicuous, are not so well able to reverberate the Sunne beames as the thicker bodies. The rayes passe singly through a diaphanous matter, but in an opacous substance they are doubled in their returne and multiplyed by reflexion. Now if the moone and the other Planets can shine so clearely by beating backe the Sunne beames, why may not the earth also shine as well, which agrees with them in the cause of this brightnesse their opacity? 2. Consider what a cleare light wee may discerne reflected from the earth in the middest of Summer, and withall conceive how much greater that must bee which is under the line, where the rayes are more directly and strongly reverberated.