Strabo, Geography (English) (XML Header) [genre: prose] [word count] [Str.]. | ||

<<Str. 2.1.24 | Str. 2.1.29 (Greek English(2)) | >>Str. 2.1.31 |

In the Third Section it is true he does make some mistakes, which we shall take into consideration; but they are
nothing like the amount which Hipparchus attributes to
him. However, we will examine his objections. [In the
first place,] he would have the ancient charts left just as
they are, and by no means India brought more to the south,
as Eratosthenes thinks proper. Indeed, he asserts that the
very arguments adduced by that writer only confirm him the
more in his opinion. He says, According to Eratosthenes,
the northern side of the third section is bounded by a line of
10,000 stadia drawn from the Caspian Gates to the Euphrates,
the southern side from Babylon to the confines of Carmania
is a little more than 9000 stadia. On the western side, following the course of the Euphrates, from Thapsacus to Babylon
there are 4800 stadia, and thence to the outlets of the river
3000 stadia more. Northward from Thapsacus [to the Gates
of Armenia] is reckoned

We answer, that if the Caspian Gates and the boundary line of Carmania and Persia were exactly under the same meridian, and if right lines drawn in the direction of Thapsacus and Babylon would intersect such meridian at right angles,

the inference would be just. ^{[Note]} For then the line [from the
common frontier of Carmania and Persia] to Babylon if produced to the meridian of Thapsacus, would appear to the eye
equal, or nearly equal, to that from the Caspian Gates to
Thapsacus. Consequently, Babylon would only be east of
Thapsacus in the same proportion as the line drawn from the
Caspian Gates to Thapsacus exceeds the line drawn from the
frontier of Carmania to Babylon. ^{[Note]} Eratosthenes, however,
does not tell us that the line which bounds the western coast
of Ariana follows the direction of the meridian; nor yet that
a line drawn from the Caspian Gates to Thapsacus would form
right angles with the meridian of the Caspian Gates. But
rather, that the line which would form right angles with the
meridian, would be one which should follow the course of the
Taurus, and with which the line drawn from the Caspian
Gates to Thapsacus would form an acute angle. Nor, again,
does he ever say that a line drawn from Carmania to Babylon
would be parallel to that drawn [from the Caspian Gates] to
Thapsacus; and even if it were parallel, this would prove
nothing for the argument of Hipparchus, since it does not
form right angles with the meridian of the Caspian Gates.
2.1.29

But taking this for granted, and proving, as he imagines, that, according to Eratosthenes, Babylon is east of Thapsacus rather more than 1000 stadia, he draws from this false hypothesis a new argument, which he uses to the following purpose; and says, If we suppose a right line drawn from Thapsacus towards the south, and another from Babylon perpendicular thereto, a right-angled triangle would be the result; whose sides should be, 1. A line drawn from Thapsacus to Babylon; 2. A perpendicular drawn from Babylon to the meridian of Thapsacus; 3. The meridian line of Thapsacus. The hypotenuse of this triangle would be a right line drawn from Thapsacus to Babylon, which he estimates at 4800 stadia. The perpendicular drawn from Babylon to the meridian of Thapsacus is scarcely more than 1000 stadia; the same amount by which the line drawn [from the Caspian Gates] to

Thapsacus exceeds that [from the common frontier of Carmania and Persia] to Babylon. The two sides [of the triangle] being given, Hipparchus proceeds to find the third,
which is much greater than the perpendicular ^{[Note]} aforesaid. To
this he adds the line drawn from Thapsacus northwards to
the mountains of Armenia, one part of which, according to
Eratosthenes, was measured, and found to be ^{[Note]}
From the parallel of Athens ^{[Note]} to that of Babylon he shows
that there cannot be a greater distance than 2400 stadia, even
admitting the estimate supplied by Eratosthenes himself of
the number of stadia which the entire meridian contains; ^{[Note]}
and that if this be so, the mountains of Armenia and the
Taurus cannot be under the same parallel of latitude as
Athens, (which is the opinion of' Eratosthenes,) but many
thousand stadia to the north, as the data supplied by that
writer himself prove.

But here, for the formation of his right-angled triangle, Hipparchus not only makes use of propositions already overturned, but assumes what was never granted, namely, that the hypotenuse subtending his right angle, which is the straight line from Thapsacus to Babylon, is 4800 stadia in length. What Eratosthenes says is, that this route follows the course of the Euphrates, and adds, that Mesopotamia and Babylon are encompassed as it were by a great circle formed by the Euphrates and Tigris, but principally by the former of these rivers. So that a straight line from Thapsacus to Babylon would neither follow the course of the Euphrates, nor yet be near so many stadia in length. Thus the argument [of Hipparchus] is overturned. We have stated before, that supposing two lines drawn from

the Caspian Gates, one to Thapsacus, and the other to the mountains of Armenia opposite Thapsacus, and distant therefrom, according to Hipparchus's own estimate, 2100 stadia at the very least, neither of them would be parallel to each other, nor yet to that line which, passing through Babylon, is styled by Eratosthenes the southern side [of the third section]. As he could not inform us of the exact length of the route by the mountains, Eratosthenes tells us the distance between Thapsacus and the Caspian Gates; in fact, to speak in a general way, he puts this distance in place of the other; besides, as he merely wanted to give the length of the territory between Ariana and the Euphrates, he was not particular to have the exact measure of either route. To pretend that he considered the lines to be parallel to each other, is evidently to accuse the man of more than childish ignorance, and we dismiss the insinuation as nonsense forthwith.

Strabo, Geography (English) (XML Header) [genre: prose] [word count] [Str.]. | ||

<<Str. 2.1.24 | Str. 2.1.29 (Greek English(2)) | >>Str. 2.1.31 |