Where A represents the Sun, B the Earth, and C the Moone; Now suppose the Moone C to be in a sextile of increase, when there is onely one small part of her body enlightened, then the earth B will have such a part of its visible Hemispheare darkened, as is proportionable to that part of the Moone which is enlightened; and as for so much of the Moone, as the Sun beames cannot reach unto, it receives light from a proportionall 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 Moone. Now the greatest difference which makes them unlike, is this, that the Moone enlightens our earth round about, whereas our earth gives light onely to that Hemispheare of the Moone which is visible unto us, as may be certainly gathered from the constant appearance of the same spots, which could not thus come to passe, if the Moone had such a diurnall 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 turne her body round, that we may discerne both Hemispheares, for according to that hypothesis, the motion of her eccentrick, doth turne her face towards us, as much as the other doth from us. But now if any question what they doe for a Moone who live in the upper part of her body? I answer, the solving of this is the most uncertaine and difficult thing that I know of concerning this whole matter. But yet I will give you two probable conjectures. 1. Perhaps, the upper Hemispheare of the Moone doth receive a sufficient light from those planets about it, and amongst these _Venus_ (it may be) bestowes a more especiall brightnesse, since _Galilæus_ hath plainly discerned that she suffers the same increase and decreases, as the Moone hath, and ’tis probable that this may be perceived there without the help of a glasse, because they are farre neerer it than wee. When _Venus_ (saith _Keplar_) lies downe in the Perige or lower part of her supposed Epicycle, then is she in conjunction with her husband the Sunne, from whom after she hath departed for the space of ten moneths, shee gets _plenum uterum_, and is in the full. But you’ll reply, though _Venus_ may bestow some light when she is over the Moone, and in conjunction, yet being in opposition, she is not visible to them, and what shall they then doe for light? I answer, then they have none: nor doth this make so great a difference betwixt those two Hemispheares as there is with us, betwixt the places under the poles, and the line, but if this bee not sufficient, then I say in the second place that 2. Perhaps there may be some other enlightened body above the Moone which we cannot discerne, nor is this altogether improbable because there is almost the like observed in Saturne, who appeares through this glasse with two lesser bodies on each side, which may supply the office of Moones, unto each hemispheare thus: o O o