Sun, may be eaſily conceived by the Scheme of the Copernican Syſtem in the former Part. At the times of theſe Oppoſitions Venus and the Earth muſt needs appear very bright and large to them. For if Venus ſhines ſo gloriouſly to us when ſhe is new and horned, ſhe muſt neceſſarily in oppoſition to the Sun, when ſhe is full, be at leaſt ſix or ſeven times larger, and a great deal nearer to the Inhabitants of Mercury, and afford them Light ſo ſtrong and bright, that they have no reaſon to complain of their want of a Moon. What the Length of their Days are, or whether they have different Seaſons in the Year, is not yet diſcovered, becauſe we have not yet been able to obſerve whether his Axis have any inclination to his Orbit, or what Time he ſpends in his diurnal Revolution about his own Axis. And yet ſeeing Mars, the Earth, Jupiter and Saturn, have certainly ſuch Succeſſions, there’s no reaſon to doubt but that he has his Days and Nights as well as they. But his Year is ſcarce the fourth part ſo long as ours. The Inhabitants of Venus have much the ſame Face of Things as thoſe in Mercury, only they never ſee him in oppoſition to the Sun, which is occaſioned by his never removing above 38 degrees, or thereabouts, from it. The Sun appears to them larger by half in his Diameter, and above twice in his Circumference, than to us: and by conſequence affords them but twice as much Light and Heat, ſo that they are nearer our Temperature than Mercury. Their Year is compleated in ſeven and a half of our Months. In the Night our Earth, when ’tis on the other ſide of the Sun from Venus, muſt needs ſeem much larger and lighter to Venus than ſhe doth ever to us; and then they may eaſily ſee, if their Eyes be not weaker than ours, our conſtant Attendant the Moon. I have often wonder’d that when I have view’d Venus when ſhe is neareſt to the Earth, and reſembled an Half-moon, juſt beginning to have ſomething like Horns, through a Teleſcope of 45 or 60 Foot long, ſhe always appeared to me all over equally lucid, that I can’t ſay I obſerved ſo much as one Spot in her, tho’ in Jupiter and Mars, which ſeem much leſs to us, they are very plainly perceiv’d. For if Venus had any ſuch Thing as Sea and Land, the former muſt neceſſarily ſhow much more obſcure than the other, as anyone may ſatisfy himſelf, that from a very high Mountain will but look down upon our Earth. I thought that perhaps the too brisk Light of Venus might be the occaſion of this equal appearance; but when I uſed an Eye-glaſs that was ſmok’d for the Purpoſe, it was ſtill the ſame Thing. What then, has Venus no Sea, or do the Waters there reflect the Light more than ours do, or their Land leſs? Or rather (which is moſt probable in my Opinion) is not all that Light we ſee reflected from an Atmoſphere ſurrounding Venus, which being thicker and more ſolid than that in Mars or Jupiter, hinders our ſeeing any thing of the Globe it ſelf, and is at the ſame time capable