It is likewise said, that in the town of Syene, which is 5000 stadia south of Alexandria[508], there is no shadow at noon, on the day of the solstice; and that a well, which was sunk for the purpose of the experiment, is illuminated by the sun in every part. Hence it appears that the sun, in this place, is vertical, and Onesicritus informs us that this is the case, about the same time, in India, at the river Hypasis[509]. It is well known, that at Berenice, a city of the Troglodytæ, and 4820 stadia beyond that city, in the same country, at the town of Ptolemais, which was built on the Red Sea, when the elephant was first hunted, this same thing takes place for forty-five days before the solstice and for an equal length of time after it, and that during these ninety days the shadows are turned towards the south[510]. Again, at Meroë, an island in the Nile and the metropolis of the Æthiopians, which is 5000 stadia[511] from Syene, there are no shadows at two periods of the year, viz. when the sun is in the 18th degree of Taurus and in the 14th of Leo[512]. The Oretes, a people of India, have a mountain named Maleus[513], near which the shadows in summer fall towards the south and in winter towards the north. The seven stars of the Great Bear are visible there for fifteen nights only. In India also, in the celebrated sea-port Patale[514], the sun rises to the right hand and the shadows fall towards the south. While Alexander was staying there it was observed, that the seven northern stars were seen only during the early part of the night[515]. Onesicritus, one of his generals, informs us in his work, that in those places in India where there are no shadows, the seven stars are not visible[516]; these places, he says, are called “Ascia[517],” and the people there do not reckon the time by hours[518].
CHAP. 76. (74.)—-WHERE THIS TAKES PLACE TWICE IN THE YEAR AND WHERE THE SHADOWS FALL IN OPPOSITE DIRECTIONS.
Eratosthenes informs us, that in the whole of Troglodytice, for twice forty-five days in the year, the shadows fall in the contrary direction[519].
CHAP. 77. (75.)—WHERE THE DAYS ARE THE LONGEST AND WHERE THE SHORTEST.
Hence it follows, that in consequence of the daylight increasing in various degrees, in Meroë the longest day consists of twelve æquinoctial hours and eight parts of an hour[520], at Alexandria of fourteen hours, in Italy of fifteen, in Britain of seventeen; where the degree of light, which exists in the night, very clearly proves, what the reason of the thing also obliges us to believe, that, during the solstitial period, as the sun approaches to the pole of the world, and his orbit is contracted, the parts of the earth that lie below him have a day of six months long, and a night of equal length when he is removed to the south pole. Pytheas, of Marseilles[521], informs us, that this is the case in the island of Thule[522], which is six days’ sail from the north of Britain. Some persons also affirm that this is the case in Mona, which is about 200 miles from Camelodunum[523], a town of Britain.
CHAP. 78. (76.)—OF THE FIRST DIAL.
Anaximenes the Milesian, the disciple of Anaximander, of whom I have spoken above[524], discovered the theory of shadows and what is called the art of dialling, and he was the first who exhibited at Lacedæmon the dial which they call sciothericon[525].
CHAP. 79. (77.)—OF THE MODE IN WHICH THE DAYS ARE COMPUTED.
The days have been computed by different people in different ways. The Babylonians reckoned from one sunrise to the next; the Athenians from one sunset to the next; the Umbrians from noon to noon; the multitude, universally, from light to darkness; the Roman priests and those who presided over the civil day, also the Egyptians and Hipparchus, from midnight to midnight[526]. It appears that the interval from one sunrise to the next is less near the solstices than near the equinoxes, because the position of the zodiac is more oblique about its middle part, and more straight near the solstice[527].