INTRODUCTORY 3 



maps of the ancients. First, the traditional voyages which 

 are crystaUized in the mythical adventm^es of Jason in the 

 Argo, and of the world as known to Homer (say, 1000 B.C.), 

 and may also be represented by the map ofHecatseus (about 

 500 B.C.), showing the great river-like " Oceanus " surround- 

 ing the known lands bordering the Mediterranean (see Plate I) 

 — a poetical misrepresentation, which was corrected by 

 Herodotus in the following century. 



The second stage may be represented by the discoveries 

 of the astronomer Pytheas, a contemporary of Alexander 

 the Great, who sailed from Massilia, in the fourth century 

 B.C., through the Strait of Gibraltar, along the coasts of Spain 

 and France, penetrated to the North Sea and up the east 

 coast of the British Isles, and heard, if he did not actually 

 see it, of a land still farther north, six days' sail beyond 

 Britain, which he called Thule, and where, he reports, the 

 sea became thick and sluggish like a jelly-fish (possibly the 

 earliest record of a planktonic phenomenon, due either to 

 dense swarms of Medusae or to gelatinous masses of Diatoms). 

 He was the first scientific investigator of the Atlantic, and 

 penetrated where we have no record of others following 

 for about four centuries. Pytheas, moreover, made notable 

 contributions to oceanography in his determination of lati- 

 tudes and in ascribing the phenomena of tides to the action 

 of the moon. The state of knowledge after his explorations 

 may be illustrated by the map of Dicaearchus (about 300 B.C. 

 — a pupil of Aristotle), extending from Thule (possibly 

 Iceland) in the north-west to Taprobane (Ceylon) in the 

 south-east. 



Two names, more celebrated in other spheres of knowledge 

 but belonging to this period, requu'e passing mention. 

 Plato's myth of the lost '' Atlantis," a mass of land in the 

 external sea beyond the Pillars of Hercules, which disap- 

 peared in a day and a night, rendering the Atlantic muddy 

 and unnavigable, has given rise throughout the ages to 

 many attempts to interpret this tradition by means of 



