The Interior of Africa

Ptolemy deals with Africa west of Egypt and below latitude 30N in chapter 6 of Book IV: he calls this area Interior Libya. As its eastern limit he sets a line that runs to the south from the coast of the Mediterranean to 310 S along his meridian 5115 P (= 2333E of Greenwich). The extreme limit to the south is the southernmost limit of Lake Victoria. Apparently a horizontal line was drawn along the southern limit of Lake Victoria, the main source of the Nile. In this section called “Interior Libya,” Ptolemy describes the part of Africa that goes from Kerne to the Theon Ochema, the Seat of the Gods. This part has been considered totally confused with errors of latitude of as much as 20, whereas Ptolemy tends to be substantially correct in matters of latitudeand even his apparent errors of longitude have an explanation.

Ptolemys calculation of longitudes for Interior Libya is distorted because he confused the Atlas-Pillar of the Sky with the Great Atlas. This is an error that occurs in Pliny, who criticizes Polybius for having placed the inner part of the Gulf of Guinea in line with the Atlas.

The data about the internal points of what Ptolemy calls Interior Libya were convincingly explained by ~~~. I have only to modify the starting point because this author did not follow a correct interpretation of the voyage of Hanno and hence the position along the coast. In describing the inland parts of the area that Ptolemy calls Interior Libya, he follows what must have been the lines that were of interest to Kerne. Ptolemy describes a trade route that begins in the land of the Autolalai that is, just east of Kerne, proceeds to the south, reaching the upper course of the Senegal, and then moves to the Niger. The position of Timbuktu (1650N, 300 W) which is called Thamoudakana, is given as 17N, 23 P = 311E. There is a certain displacement in longitude because Promontory Rhysadion as Cape Sierra Leone, which is near the source of the Niger, was confused with Cape St. Paul. The first part of the route begins in the land of the Autolalai at 2350N, 10 P, which must be the salt mine of Jyil. It reaches the Senegal at a place called Magura, 15N 1230P, and ascends its course through Ubrix, 1320N, 1420P, and Iarzitta, 1215N, 1620P. Another route moves to the Niger.

Cape Hesperion is placed at about 333 W of Greenwich, whereas it is at 750. Pliny places the Gulf called Hesperion or Great in the external sea (our Atlantic, in opposition to the Mediterranean) at 14 P 4 ( = 310 W).

For the stretch between Cape Verde and Mount Cameroon, Ptolemy followed two sources of information. The first source of information provided the data between Cape Verde and Cape Palmas.

The description of the coast to the north of Cape Palmas is hopelessly distorted, because Ptolemy confused the Islands of Cape Verde with the Canary Islands. Ptolemy enters at 1730 W, (= 930P) a Cape Soloention which proves to be Cape Verde (1730 W, 1443N). As Vivien de Saint-Martin observed, this is the Cape Surrentium of Pliny. But Ptolemy confused Cape Soloention with Cape Soleis. He mentions Cape Soleis as the Mountain of Helios (this is based on Latin sources that interpret Soleis as Mons Solis, “Mountain of the Sun”) and places it at 3115N, 645 P (= 832 W). This is the location of Cape Cantin 3237N 919 W. Ptolemy placed to the north and south of Cape Soloention localities that belong to the north and south of Cape Soleis. But one can identify also locations that were really related to Cape Verde. To the south of Cape Soloention, Ptolemy mentions a Great Harbor (Magnus Portus) at 14N 10 P which proves to be the Great Opening of Hanno and the Palsum of Pliny (Geba Estuary, 1443N 1209 W), 2_ east of Cape Verde, which is correct. Then he mentions a Baba City at 13N 1030 P which is to be identified with the River Bambotum of Pliny (Shebar Entrance 723N 1232 W). Apparently he had an accurate datum for the latitude of Cape Verde, but he had to guess the latitude of the Palsum and Baba City, which he knew were to the south of it.

The confusion between the Canary Islands and the Islands of Cape Verde cause Ptolemy to miss the data about longitude for the stretch between Kerne and the Theon Okhema: he presents the coast as moving in a more or less straight north-south direction from Kerne to Cape St. Paul, the beginning of the Bight of Benin or Horn of Hesperos. Cape St. Paul is merged with Cape Sierra Leone (830N, 1318 W); it is called Promontory Rhysadion and placed at 1130N, 830 P (= 718E). Ptolemy states that Mount Rhysadion out of which there originates the Stachiris or Volta river, is near the mountain from which there originates the Nia or Niger river. By the error of 10 in longitude he merged into one the chain of mountains that ends at Cape St. Paul and from which there originates the Stachir or Volta river with the mountains of Sierra Leone from which there originates the Nia or Niger river. But he started with data that were accurate: Cape Sierra Leone, since it is most close to latitude 0 P = 1322 W, must have been an anchor point in the geographical system that Ptolemy followed. It is near the sources of the Niger. From Cape Rhysadion to the Support of the Gods, Ptolemys data about longitude are substantially correct, granted the correction of 10.

In the description of the coast between Kerne and Cape Rhysadion there can be recognized the mouth of the Nuios River (1820N, 10 P) which is the Senegal. Since it was conceived that the Senegal and the Niger were a continuation of each other, the latter is called Nia. Possibly both names are derived from that of the Nile, since it was assumed that through the river Oceanus the Nile continued through the Niger and the Senegal. The mouth of the Nuios or Senegal is placed at 1820N 10 P.

After Kerne and the Island of Hera, Ptolemy describes the Islands of the Blessed, which are obviously the group of Cape Verde. They are placed between latitude 16 and latitude 1030 and between longitude 0 and 01. The names are those of the Canary Islands, and longitude 0 of Ptolemy corresponds to Isla Alegranza.

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As far as longitudes are concerned, Ptolemy started with the datum of 5 for the north-east corner of the rectangle of Atlantis and imagined that the coast moved steadily in a WNW direction. Cape St. John is at 058E. The difference of about 8 is caused by the confusion of the Canary Islands with the Islands of Cape Verde. The river Gambia is called Stachiris. The mouth of the Niger, called Nia, is placed at 1330P, that is, 530 (= 406) east of Cape Rhysadion, whereas the mouth of the Niger at Forcados (520E) is 416 east of Cape St. John. Under the name of Promontory of the Horn of Hesperos he mentions Cape Formoso (415N, 458E) which separates the Bight of Benin from the Bight of Biafra; since it is a promontory, Ptolemy made it extend to the west as far as 13 P. Next he mentions the Hippodromos of Ethiopia at 515 14 P. As I have said the source used by Ptolemy

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Ptolemy places the Seat of the Gods 5 north of the Equator at longitude 19 P (015 W). The interval of 5 corresponds to the 300 stadia of Plato. He places the Hippodromos of Ethiopia at 5N, 15 14 P. Here we find the same error that occurs in Platos sourcehippodromos for hypodromos. This is the Great Island of Hanno between the Sombrero River and New Calabar River. The longitude 14 P (=320 W) can be corrected by adding the 10 caused by the confusion between the Canary Islands and the Islands of Cape Verde. The Hippodromos is placed 5 (=336) west of the Seat of the Gods; the figure is the same as that of Plato, that is, 2000 stadia = 320, but Ptolemy counts by the extreme northern and western limit of the Hippodromos which has a radius of 12, rounded by Ptolemy to 15.

Ptolemy states that a river Masitholos begins at the Seat of the Gods (Mount Cameroon) and ends at 640N 14 P. Apparently he took the line along the northern side of the rectangle of Atlantis as a river, one that goes to the point where the mentioned branch separated from the main course of the Nile. Plato says that it was a canal and that it received the water of the rivers. Ptolemy continued with that branch of the Nile that goes to the Hippodromos. He took the beginning of this branch as the mouth of the Masitholos.

Next, Ptolemy mentions the mouth of the Nia River at 640N 14 P; this proves to be the mouth of the Niger at Forcados (522N 526E). He places it 530 = 357 W of the Seat of the Gods, which is correct. By the Horn Hesperon he means the Bight of Benin. Having mentioned the mouth of the Niger, that closes it to the east, he places its innermost place at 8N 13 P. This means that the deep end of the Gulf that begins at Cape Palmas is 120 north of the mouth of the Nia river and 1 (actually _ or 43) west of the mouth of the Niger. This indicates that he correctly placed the deep end of the Gulf at Benin. But he did not understand that Hesperon Horn refers to a gulf and not to a cape and hence wrote “Promontory of the Gulf of Hesperos.” Finally, he lists a Rhysaion Cape, at 1130N, 830 P., specifying that the Hesperon Horn begins there. He must be referring to Cape Saint Paul (550N 058E), which may be taken as the beginning of the Gulf of Benin. He places it 5 = 335 west of the mouth of the NiaCape St. Paul is 4 west of the Niger at Forcados.

After this Ptolemy lists the Mouth of the Stachiris River at 930P, followed at 11P by the Port of the Perorsoi (“the completely-burned Aiethiopians”), which may be Lagos. Cape Formoso at 415N, 458E, which is the separation between the Bight of Benin and the Bight of Biafra, is called Promontory of the Gulf of Hesperos and placed at 13 P = 556E. The mouth of the Nia or Niger River is placed at 1330P = 639 W; up to recently the main mouth of the Niger was at ~~~. After this there is mentioned the Hippodromos of Ethiopia which I have already discussed.

I have listed the only data for the area below latitude 30N that reveal any semblance of accuracy. But the data about the Bight of Biafra and the Bight of Benin in the Gulf of Guinea prove much more accurate. Here Ptolemy used the same data that were available to Plato. Apparently, Ptolemy had access to a detailed description of the Bight of Biafra, the source of information that was available to Plato. It may have been concerned with revealing the achievements of the Benin culture and hence may have been the source of Platos detailed anthropological information. This source gave also the latitude of Kerne, called Island of Hera, and the latitude of Cape Verde, and mentioned the Great Opening and the Bambotum. The only accurate description of Western Africa concerns points significant in the Periplus of Hanno.

Ptolemy placed the Island of Kerne at 2540N, 5 P (=1058 W), but mentioned next to it also an Island of Hera at 2350N, 8 P (=557 W). Apparently the two data concern the same place; it may be that the Carthaginians dedicated Kerne to their chief goddess Tanit (Hera). The Island of Hera is described as being “against the Autolalai,” that is, at the latitude of the Atlas; the name of the Atlantes, inhabitants of Atlas-Pillar of the Sky, is interpreted into Greek as Autolalai, “those who babble to themselves.” Ptolemy had a correct datum, 2350N, for the latitude of Kerne and Atlas-Pillar of the Sky in the Ahaggar.

After the voyage of Hanno it was no longer possible to take the Canary Islands as the westernmost point in the Oikoumene, so that the name of the Islands of the Blessed shifted to the Islands of Cape Verde.

Pliny states that the geography of the Islands of the Hesperides is most confused. The reason for this is that they could be placed either at the south in correspondence with the southern end of the Nile, or to the extreme West. Statius Sebosus gave the name of islands of the Gorgones to the Canary Islands, placed against the Atlas, meaning the Chain of the Atlas, and called Island of the Hesperides the islands of the Bight of Biafra, which he called Horn of Hesperos. But others placed the Islands of the Blessed near some islands of Mauretania that were discovered by Juba “against the coast of the Autolalai”. Pliny mentions that in these islands, called Purpuriae, Juba established a dyeing industry that used Gaetulian purple, but that he is not certain as to their whereabouts. Ptolemy places the Autolalai at the latitude of Kerne.

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Early Greek writers speak of the Islands of the Blessed which are at the limit of the world, to the extreme west, beyond the Atlas. It is agreed by many that they are speaking of the Canary Islands. The question is that of knowing whether the Atlas in question is the Chain of the Atlas or Atlas-Pillar of the Sky.

Pliny continues by providing some very specific numerical data that have been considered most obscure because scholars have refused to accept as possible that the ancients had any knowledge of the Islands of Cape Verde. It is stated that from Gades or Cadiz (3626N) to the island of Iunonia (it is usually identified with Isla Ferteventura 2924N in the group of Canary Islands, but I identify it with Isla Alegranza for reasons that I shall explain) there are 750 Roman miles, that is, 10. “From there, it is just as far westward” to the islands Pluvialia and Capraria, says Pliny, and I understand him to mean that one must count 10 (or 750 miles) more to the south, making a total of 20, (or 1500 miles from Gades) and also 10 (or 750 miles) to the west. The islands are Ilha Sal (1635N 2254 W) and Ilha Boa Vista, the easternmost ones (1613N 2256 W) of the Windward group of the Islands of Cape Verde, 10 to the west of the island of Fuerteventura in the Canary group. “In Pluvialia there is no water except rain water,” reports Pliny (VI 202); Ilha Sal is described as esteril e seca. . . Toda a alimentaçao é importada, inclusivamente a agua.

Pliny continues by reporting that beyond these islands are the Islands of the Blessed. According to Statius Sebosus, to reach these islands one had to sail 250 miles further. This is the correct distance WNW to the two westernmost of the Windward islands, counting from Boa Vista. The Islands of the Blessed are São Vicente (1653N 2500N) and Santo Antao (1704N 2522 W). Santo Antao was called Invallis “because of its convexity” ; in fact, there the mountains form deep enclosed areas which are unusually fertile for the barren and dry islands of Cape Verde: “On it trees grow to a height of 140 feet.” The statement that the island has a circuit of 300 miles is exaggerated, since the circuit is about 120 km. The other island, called Planasia, is São Vicente which does not have high mountains and in which a large plateau slopes down towards the excellent harbor of Porto Grande. Pliny then proceeds to explain the position of the Island of the Blessed in relation to the islands of the Purpurariae, after having stated earlier that the position of the latter was obscure to him. The Purpurariae are the two Leeward islands in the group of Cape Verde, Ilha do Fogo (1450N, 2419 W) and Ilha de São Tiago (1455N, 2332 W). Juba said that starting from the Purpuriae and going 250 miles to the north of west and then 375 miles east, one reaches Ombrios, “Rain Island,” which obviously is Pluvialia, called by a Greek name. This statement has been considered an impossible riddle, but it is comprehensible when one considers that the Islands of Cape Verde are usually described as forming a sort of semicircle. Today we divide the Islands of Cape Verde into two groups, the Leeward ones to the south of which São Tiago is the most important, and the Windward group to the north. In the description quoted by Pliny a distinction is made between the two of the Windward islands to the extreme east, which are Ilha Boa Vista with the smaller Ilha Sal, and the two at the extreme west, which are Ilha São Antão and Ilha São Vicente. Starting from São Tiago, the most important of of the Leeward group, one goes 375 miles NW to Ilha São Antão and then 250 miles east to Ilha Sal, thereby covering the entire expanse of the archipelago.

At this point Pliny, or better, his source, introduces the real element of confusion: Since the last island mentioned was Ombrios or Pluvialia and there was a Pluvialia in the Canary Islands, to the mention of Ombrios Pliny introduces, without giving distances, a listing and description of the Canary Islands. This confusion is a consequence of the earlier conception by which the Islands of the Blessed were the Canary Islands.

Actually the only element of confusion is the merging into one entity of the Canary Islands with the Islands of Cape Verde. Ptolemy made use among others of the source followed by Pliny. He has the following entry:

Islands that are near Libya in the Occidental Oceanus:
Kerne Island 2540N 5 P
Island of Hera against the Autolalai 2350N,8P

Ptolemy lists six islands called Islands of the Blessed which he arranges on a line between his longitude 0 and 1

Inaccessible Island 160P
Island of Hera 1515N,1P
Pluvialia Island 1415N,0P
Capraria Island 1230N,0P
Canaria Island 11,1P
Purpuraria Island 1030N,0P

Longitude 0 P = 1322 W is that of the easternmost of the Canary Islands (Isla Lanzarote 1329 W), but the latitude is that of the Islands of Cape Verde. As a result there is a shift of about 10 in the longitude of the coast between Kerne and the Support of the Gods. The latter is placed at 5N,19P = 018E, whereas Mount Cameroon is at 413N,910E.

Apparently Ptolemy could not decide whether Kerne was to the south or to the north of the Island of Hera, since this could be either in the Canary Islands or in the Islands of Cape Verde. He assigned the latitude of Kerne Island 2350N to the Island of Hera, and placed Kerne at 2540N. The latitude 2540N is obtained by following the reckoning mentioned by Pliny, 750 miles or 10 south of Gades or Cadiz. To Kerne there is assigned a longitude 8 P=545 W, whereas the correct longitude is 1548 W, with the difference of 10 I have mentioned earlier. Ptolemy apparently had a source that gave the position of Kerne and the island of Hera together and gave their respective positions, with the result that he exchanged their latitudes.

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Ptolemy mentions a line drawn from the Congo point to the External Sea, that is, our Atlantic, to a gulf that is called Great or Hesperion; he refers to the Gulf of Guinea which is so called by Hanno.

The line goes almost horizontally from the Congo point to Cape Hesperion or Cape Palmas placed at 4N,14E. The latitude of Cape Palmas is 427N.

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The geodetic point known as Island of the Gorgones is obtained by counting 2351 from the Main Axis of Egypt: 3114E - 2351 = 723E. The corresponding point to the north is 4742N 823E. It appears that this point was identified with the Rheinfall which is at 4742N 836E. Ptolemy places the origin of the Rhine River at 46N 2920P.

Quem procul a patria diverso maximus orbe

Excipit Eridanus fumantiaque abluit ora.

On the same meridian in Africa there was the geodetic point Chariot of the Gods which may have received that name for the same reason, because it is the western point at which the chariot of the Sun comes to the end of its course. .cp .fb dump