A Source Book in Greek Science

Contents:
Author: Claudius Ptolemy

GEOGRAPHY

A General Description of the Map of the Inhabited Portion of the Earth

Ptolemy, Geography VII. 5 (Nobbe)

The portion of the earth that we inhabit2 was divided into three continents by the ancients, who gave accurate accounts about each of them and have left, as the fruits of their investigation, written descriptions dealing with each. Now we, too, on the basis in part of our own observations and in part of careful selection from their work, have endeavored to make a representation of the entire inhabited portion of the earth in the form of a map, so that every useful detail may be available to lovers of knowledge, useful, that is, for equipping their minds with information, and capable of arousing the keen interest which is natural to them.

The portion of the earth that we inhabit is bounded on the east by an unknown land that adjoins the eastern peoples of Asia Major, the Sinae and the inhabitants of Serica; on the south too by unknown lands, which enclose the Indian Sea and bound the country in the south of Libya called Ethiopia Agisymba; on the west by the unknown land that embraces the Ethiopian gulf of Libya, and thereafter by the western Ocean which lies along the westernmost parts of Libya and Europe; and on the north by the Ocean continuous [with the western Ocean] which surrounds the Britannic Islands and the northernmost parts of Europe and is called the Duecaledo-nian and the Sarmatic Seas, and also by the unknown land that borders on the northernmost countries of Asia Major, Sarmatia, Scythia, and Serica.

Of the seas contained within the inhabited portion of the earth, our sea,3 together with the smaller seas that are a part of it the Adriatic, the Aegean, the Propontis and the Pontus, and the Sea of Maeotis—opens into the Ocean only at the straits of Heracles, like a peninsula having as its isthmus, as it were, these straits of Heracles. But the Hyrcanian or Caspian Sea is surrounded on all sides by land, like an island with land and sea reversed.

Similarly, the whole Indian Sea, along with the gulfs that are connected with it, the Arabian, Persian, Gangetic, and that properly called the Great Gulf, is entirely surrounded by land.

And so, of the three continents Asia is joined to Libya by the isthmus of Arabia, which also separates our sea from the Arabian Gulf, and also by the unknown land that surrounds the Indian Sea. Again Asia is joined to Europe by the isthmus between the Sea of Maeotis and the Sarmatic Ocean at the passage of the Tanais River. Libya is separated from Europe only by the strait,1 and while not directly joined to Europe, is yet indirectly connected with it through Asia. For Asia is continuous with both Europe and Libya, being contiguous with them in the east.2

Now the largest of the three continents is Asia, second largest Libya, and third Europe. Of the seas that were said to be entirely surrounded by land, the largest is the Indian Sea, second largest our own, third the Hyrcanian or Caspian. Again, the more important gulfs, in order of size, are as follows: first the Gangetic, second the Persian, third the Great Gulf, fourth the Arabian,3 fifth the Ethiopian, sixth Pontus, seventh the Aegean, eighth the Sea of Maeotis, ninth the Adriatic, and tenth the Propontis.

Of the more important islands or peninsulas the largest is Taprobane,4 second largest Albion of the Britannic Islands, third the Golden Chersonese,5 fourth Hibernia of the Britannic islands, fifth the Peloponnesus, sixth Sicily, seventh Sardinia, eighth Cyrnus,6 ninth Crete, tenth Cyprus.

On the assumption that a great circle contains 360° the southern limit of the known portion of the earth is indicated by the parallel of latitude 16°25′ south of the equator, the parallel through Meroe being the same distance north of the equator. The northern limit is indicated by the parallel 63′ north of the equator, drawn through the island of Thule. Thus the entire latitude of the known earth is 79°25′ or, approximately, 80′, and in stades approximately 40,000. That is, one degree contains 500 stades, as has been ascertained by the more exact measurements. The circumference of the whole earth is 180,000 stades.7

Again, the eastern limit of the known portion of the earth is indicated by the meridian drawn through the chief city of the Sinae, 119º30′ east of the meridian through Alexandria as measured on the equator, i.e., approximately eight equinoctial hours. And the western limit is indicated by the meridian drawn through the Fortunate Isles, 60º30′, or four equinoctial hours, west of the meridian through Alexandria. The westernmost meridian is 180º, i.e., a semicircle, or twelve equinoctial hours, distant from the easternmost.

Thus the entire longitude of the known portion of the earth, measured along the equator, contains 90,000 stades; measured along its southernmost parallel approximately

measured along the northernmost parallel 40,000 stades; measured along the parallel through Rhodes, 36º distant from the equator, the parallel on which measurements have generally been made, approximately 72,000;1 measured along the parallel through Syene, 23º50′ distant from the equator and approximately bisecting the entire breadth, 82,336. This corresponds to the ratio between the aforesaid parallels and the equator.

Thus the longitude of the known portion of the earth is greater than its latitude, in the climata furthest north, by approximately

of the latitude; in those near the parallel through Rhodes by approximately
; in those near the parallel through Syene by the amount of the latitude plus approximately
thereof; in the southernmost parts by the amount of the latitude plus approximately
thereof; in the climata near the equator by the amount of the latitude plus ¼ thereof.

And the length of the longest day or night on the southernmost of the aforesaid parallels is 13 equinoctial hours (just as on the parallel through Meroe), on the equator 12 hours, on the parallel through Syene

hours, on that through Rhodes
, on the northernmost parallel, that through Thule, 20. The difference over the whole latitude is nine equinoctial hours.2

2 The use of "we"

in this technical phrase seems to recognize the possibility of the existence of another inhabited region situated in the southern hemisphere (see p. 159), but Ptolemy is not consistent in his usage.

3 I.e., the Mediterranean.

1 I.e., of Heracles.

2 I.e., east from the point of view of Europe and Libya.

3 Not the modern Arabian Sea but the Red Sea.

4 Ceylon.

5 The Malay Peninsula.

6 Corsica.

7 See p. 150, n. 2.

1 A variant, 72,812, accords better with the fraction

below. But see p. 173.

2 At the summer solstice the length of the day on the parallel through Thule is 20 hours, whereas on the southernmost parallel it is 11 hours.

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Chicago: Claudius Ptolemy, "A General Description of the Map of the Inhabited Portion of the Earth," A Source Book in Greek Science, ed. Nobbe in A Source Book in Greek Science, ed. Morris R. Cohen and I. E. Drabkin (Cambridge: Harvard University Press, 1948), 179–181. Original Sources, accessed October 16, 2019, http://originalsources.com/Document.aspx?DocID=4SPGH6EE3K6M4H5.

MLA: Ptolemy, Claudius. "A General Description of the Map of the Inhabited Portion of the Earth." A Source Book in Greek Science, edited by Nobbe, Vol. VII, in A Source Book in Greek Science, edited by Morris R. Cohen and I. E. Drabkin, Cambridge, Harvard University Press, 1948, pp. 179–181. Original Sources. 16 Oct. 2019. originalsources.com/Document.aspx?DocID=4SPGH6EE3K6M4H5.

Harvard: Ptolemy, C, 'A General Description of the Map of the Inhabited Portion of the Earth' in A Source Book in Greek Science, ed. . cited in 1948, A Source Book in Greek Science, ed. , Harvard University Press, Cambridge, pp.179–181. Original Sources, retrieved 16 October 2019, from http://originalsources.com/Document.aspx?DocID=4SPGH6EE3K6M4H5.