And next her Mother's Head it cuts, and then Then of the Solftitial Colure Crofs this, and from the Pole doth first appear And through its Neck; which, when the Sun retires, The hinder Paws o' th' Bear, and near the Pole Lib. I. Thus much, at prefent, is fufficient concerning the Colures; let me now proceed to the Tropics. Euphrof. Why are thofe two Circles called the Tropics, Cleonicus? Cleon. To understand the Reafon thereof nicely, you muft know, (which you will eafily obferve) that while the Sun is going from Aries to Cancer, he advances every Day more Northward than before he was, till being come to Cancer, he is moft northerly that he can be; after which, as he defcends to Libra, he gets ever Day more Southward than before. Now, when he is in the Beginning of Cancer, it is, that he changes his Motion, and turns from going Northward to go Southward: Now this Turning back of the Sun was by the Greeks called Trope; from whence the Parallel paffing through the Beginning of Cancer is called the Tropic of Cancer. Euphrof. Very good, I understand you well; and I fee alfo the fame Reafon, why the other is called the Tropic of Capricorn, because there the Sun returns from the foutherly Course to his northern one. But, pray, what is reprefented by thefe Tropics on the Sphere? Cleon. Thefe Tropics reprefent (for any Latitude) the longest and forteft Days in the Year; for they fhew the Part of the diurnal Motion of the Sun, for the two Days when he is in the Beginning of Cancer and Capricorn; where he has the greateft and leaft Meridian Altitude; and confequently, when he is in the firft Minute of Cancer, all that Part of the Tropic of Cancer, which is above the Horizon, represents the Length of that Day; and all that is beneath the Horizon, represents the Night of that Day; and it is easy to obferve, from the Sphere, that the Day is the longest, and that Night the shortest of all others in the Year. In the fame Manner, the two Parts of the Tropic of Capricorn, above and below the Horizon, fhew the shortest Day and longest Night in the Year. Euphrof. I believe I apprehend your Meaning tolerably well; but you muft make fome Grains of Allowance to a Novice in these Studies.-Pray, have these Tropics any other Ufe? Cleon. They are the Boundaries between the Torrid and Temperate Zones on the terreftrial Globe, of which more hereafter. The Tropic of Cancer is thus poetically defcribed by Manilius: The Line defcrib'd through Cancer's Claws confines There, when the Sun afcends his greatest Height, Another, Southward drawn, exactly fets And whirls, in narrow Rounds, the freezing Day. Lib. I. } We are now come to the Polar Circles, which are the last to be confidered on the Sphere. Euphrof. Thefe, I remember, you told me were called the Arctic and Antarctic Circles; pray, whence do they derive these Names? Cleon. The Arctic Circle, or that about the North Pole, is fo called from Artus, the Greek Name of the Conftellation of the greater Bear, which is fituated very near it ; and the North Pole is fometimes called the Artic Pole, because it is the laft Star in the Tail of the leffer Bear; as I fhall fhew you hereafter, when we come to discourse of the Conftellations. The other is called the Antarctic Circle, as being on the oppofite Part of the Sphere to this. Euphrof. What is the Ufe of these Circles? Cleon. They fhew the Latitude on each Side the Equinoctial, where the Sun does not fet, or go below the Horizon, when he is at the greatest Distance, North and South, that is, in the Beginning of Cancer and Capricorn. Euphrof. Indeed! is there fuch a Thing as all Day, and no Night, in that Latitude? Cleon. Yes; and the nearer you go from the Polar Circle to the Pole, the longer the Sun continues above the Horizon; and precifely under the Pole, the Sun fets not for the Space of fix Months, or half a Year, as I shall demonftrate to you on the Globes hereafter; and the other half Year it is all Night; that is, the Sun is not feen from that Pole above the Horizon, which in that Cafe is the Equator itself. Euphrof. This is very wonderful; I hope I fhall underftand you better upon the Globes.-But what other Ufe do you make of thefe Circles? Cleon. They are the Boundaries between the Temperate and Frigid Zones. Thefe Circles alfo Manilius thus defcribes : One tow'rds the North fuftains the fhining Bear, Twice twelve Degrees, and thirty Minutes lefs; The Antarctic thus: The laft, drawn round the Southern Pole confines Wide as the Arctic is th' Antarctic Round. Euphrof. But before we leave this Subject, pray tell me one Thing; why are the Ends of the Axis of the Sphere called the POLES of the World? Cleon. The Word Pole is Greek, and fignifies to turn I round Cleon. The Arctic Circle, or that about the North Pole, is fo called from Artus, the Greek Name of the Conftellation of the greater Bear, which is fituated very near it ; and the North Pole is fometimes called the Arctic Pole, because it is the laft Star in the Tail of the leffer Bear; as I shall shew you hereafter, when we come to discourse of the Conftellations. The other is called the Antarctic Circle, as being on the oppofite Part of the Sphere to this. Euphrof. What is the Ufe of these Circles? Cleon. They fhew the Latitude on each Side the Equinoctial, where the Sun does not fet, or go below the Horizon, when he is at the greatest Distance, North and South, that is, in the Beginning of Cancer and Capricorn. Euphrof. Indeed! is there fuch a Thing as all Day, and no Night, in that Latitude? Cleon. Yes; and the nearer you go from the Polar Circle to the Pole, the longer the Sun continues above the Horizon; and precifely under the Pole, the Sun fets not for the Space of fix Months, or half a Year, as I shall demonftrate to you on the Globes hereafter; and the other half Year it is all Night; that is, the Sun is not feen from that Pole above the Horizon, which in that Cafe is the Equator itself. Euphrof. This is very wonderful; I hope I fhall underftand you better upon the Globes.-But what other Use you make of these Circles? do Cleon. They are the Boundaries between the Temperate and Frigid Zones. Thefe Circles alfo Manilius thus defcribes : One tow'rds the North fuftains the fhining Bear, Twice twelve Degrees, and thirty Minutes lefs; The laft, drawn round the Southern Pole confines Wide as the Arctic is th' Antarctic Round. Euphrof. But before we leave this Subject, pray tell me one Thing; why are the Ends of the Axis of the Sphere called the POLES of the World? Cleon. The Word Pole is Greek, and fignifies to turn |