VOLUME I
large vessel or receptacle. From there it goes to all the rivers, and so it continues, and no water is ever engendered within the cavities or caverns of the earth. Thus the waters are gathered together, and in this manner so many rivers, streams and springs are engendered. For this reason they commonly discharge more water, and in greater quantity in winter than in summer, and some waters fail and others do not, because those which have a very large and capacious vessel, which holds enough for all the year until it rains again the following winter, are perpetual and never dry up. While other waters have smaller vessels, holding a smaller quantity of water, and therefore dry up very easily, since their vessels are very soon emptied, before it rains again and the vessel is filled anew. As to this opinion, it is quite certain and beyond doubt, firstly that part of the earth which is ordinarily subject to very great heat of the sun, in the torrid regions, burnt by the sun, has very little water, springs or even rivers. That part which lies to the north of it is inhabited, and the part contrary or opposite to it, to the south has many springs and rivers [/fol. 2v]. But it does not therefore follow that water does not have its origin somewhere within the earth. Where there are so many great rivers, and their waters so perpetual, without ever failing nor do their few springs dry up, it is known and may be read, that the waters of the torrid regions do not always come from far away. Thus according to some geographers, the river Niger1 rises on mount Tela, and the river Masitolus on another mountain called The Carriage, which are in the interior of Libya, where it very seldom rains, for they have a continual summer, and must necessarily be short of water. Yet it appears those rivers flow throughout the year. And it appears that on the Hellespont, and other places in that stretch of country, despite the rain, springs and even rivers frequently dry up in summer, as also in parts of Germany where there are great droughts for long periods of time. So in a country like that, because of the great drought, all the waters ought to dry up on account of the long, almost continual summer; and if water were not engendered within those mountains, beside what issues from the rains alone, they would needs have to dry up. But because here in these places the waters dry up, it may be deduced, and so they conclude, that not all the water collects from rain, but some must originate in the same place. No less can it be argued that those mountains attract or drink up the water from snow that thaws in other places, which on account of the great heat [/fol. 3r] of the sun melts because of their very great height; and for this reason such lands have regular rivers, which issue continually from their springs; assuming that in places so torrid, snow falls, for if there is no rain, far less should there be snow in those lands. So the melting snow would cause those rivers to rise, especially the snows of the Niger and Masitolus, as does happen with the flooding of the river Nile, because of the 1
The river Niger1 ... Claudius Ptolemy, Geographia, IV 6.14 names mount Thala as the source of the Niger, and 'the carriage of the Gods' as the source of the Masitholus. ('Carriage' is a better translation than 'chariot of the Gods'). Thala may refer to the mountains of Tibesti in Chad, for the course of the Niger was only vaguely known to ancient geographers. The 'carriage of the Gods' has been identified with more than one mountain in what is now Guinea and Sierra Leone, and identification of the river must follow that of the mountain. Both were reported by Hanno the Carthaginian in his Vth century BC navigation: it is striking that in the 16th century AD, after all the Portuguese voyages along the West African coast, this data was still accepted as scientific fact. [84]