according to the most moderate hypothesis, must be fixed seven degrees to the south of Rhapta.  Marinus, however, fixes it either in thirty-five degrees south, or under the tropic of Capricorn.  He was led into this and similar errors by assigning too great a number of stadia to the degree.  Ptolemy endeavours to correct him, and places Prasum in latitude 15, 30 south; it is remarkable that the Prasum of Ptolemy is precisely at Mosambique, the last of the Arabian settlements in the following ages, and the Prasum of Marinus, if under the tropic of Capricorn, is the limit of the knowledge of the Arabians on this coast of Africa.

Marinus, as quoted by Ptolemy, affirms that he was in possession of the journals of two expeditions under the command of Septimus Flaccus and Julius Maternus:  the former of these officers set off from Cyrene, and the latter from Leptis; and, according to Marinus, they penetrated through the interior of Africa to the southward of the Equator, as far as a nation they styled Agesymba.  The error of Marinus with respect to the valuation of the stadium, has led him to fix this nation in twenty-four degrees south latitude; if allowance, however, be made for his error, the Agesymba will still be placed under the Equator,—­a great distance for a land expedition to have readied in the interior of Africa.  Flaccus reported that the Ethiopians of Agesymba, were three months journeying to the south of the Garamantes, and the latter were 5400 of the stadia of Marinus, distant from Cyrene.  According to the journal of Maternus, when the king of the Garamantes set off to attack the people of Agesymba, he marched four months to the south.

There are also some notices in Marinus of voyages performed along the coast of Africa, between India and Africa, and along part of the coast of India; he particularly mentions one Theophilus who frequented the coast of Azania, and who was carried by a south-west wind from Rhapta to Aromata in twenty days; and Diogenes, one of the traders to India, who on his return after he had come in sight of Aromata, was caught by the north-east monsoon, and carried down the coast during twenty-five days, till he reached the lakes from which the Nile issues.  Marinus also mentions a Diogenes Samius, who describes the course held by vessels from the Indus to the coast of Cambay, and from Arabia to the coast of Africa.  According to him, in the former voyage they sailed with the Bull in the middle of the heavens, and the Pleiades in the middle of the main yard; in the latter voyage, they sailed to the south, and by the star Canobus.