SUMMARY OF RESULTS. 
27 
tains, for these have but a slight elevation when compared with the volume of the earth. 1 
In one of Seneca’s tragedies there is the most remarkable prophecy on record, pointing 
to the discovery of America, more remarkable than the suggestion of Strabo noted above. 
An immense land, new worlds, shall in later years, he says, be disclosed in the Ocean. 2 
Pliny the Elder 3 held, as was generally admitted in his time, that the sea sur- Plin? the Elder, 
rounded the world like a girdle, which, he says, is a fact demonstrated by experience, 
and concerning which it is no longer necessary to indulge in speculations. 4 The whole 
part of the work in which he deals with the ocean is full of errors and conjectures. 
He catalogues marine animals into one hundred and seventy-six species, 5 being four less 
than the number recorded by Aristotle in the PEgean Sea alone. Pleased with his 
enumeration, he exclaims : — “ Surely, then, every one must allow that it is quite impos- His Views cox- 
sible to comprise every species of [land] animal in one general view for the information o^/nism^^ 1 ^ 
of mankind. And yet, by Hercules ! in the sea and in the ocean, vast as it is, there 
exists nothing that is unknown to us, and, a truly marvellous fact, it is with those things 
which Nature has concealed in the deep that we are best acquainted ! ” 6 
Pliny confessed himself unable to give a detailed account of the depth of the 
ocean. Some parts he stated to be 15 stadia (1500 fathoms) deep, others “immensely 
deep, no bottom having been found.” In explaining very clearly “why the sea is salt,” 
he says : — “ Hence it is that the widely-diffused sea is impregnated with the flavour of 
salt, in consequence of what is sweet and mild being evaporated from it, which the force 
of fire easily accomplishes : while all the more acrid and thick matter is left behind, on 
which account the water of the sea is less salt at some depth than at the surface.” In 
this explanation Pliny followed Aristotle. 
To about the time of Pliny must be referred the Periplus of the Erythrgean Sea — an Periplus of thf 
important work, evidently compiled for the use of those engaged in the commerce -- iTIIUj:a - x "' a 
and navigation of the Indian Ocean at that period. The author gives a very characteristic 
description of the phenomena produced at the embouchures of rivers on the coasts of 
India, now known under the name of “ bores.” 7 
During the reign of Hadrian, Flavius Arrianus wrote the Periplus of the Pontus Second Century 
Euxinus ; this work, which is simply an official report, adds little information of a p K ^ IPLCS 0F THK 
general kind to what was already known of the Black Sea, but gives copious and Pontus Euxnu 
accurate details regarding its coasts useful to navigators. 
Before considering the work of Ptolemy, a return to the ideas of Hipparchus 
1 The ideas of Seneca upon the geological action of marine and fresh water, summarised above, are found in the 
first two chapters of the third book of Quiestiones Naturales. Dr. Nehring, op. cit., whom we have followed, has arranged 
these ideas methodically, in accordance with the rules followed in modern geological text-books. 
2 “ Venient annis ssecula serfs, 
Quibus Ocean us vincula rerum 
Laxet, et ingens pateat tellus, 
Tethysque novos detegat orbes, 
Nec sit terris ultima Thule.” — Seneca, Medea , 376. J 23 to 79 A.D. 
4 Pliny, Hist. Nat., ii. 66 “Nec arguments hoc investigandum, sed jam experiinentis coguitum.” 
5 Some MSS. have 144 and some 164 species. 6 Fliny, Hist. Nat., xxxii. 53. 7 Periplu3 Maris Erythrmi, sec. 45, 46. 
