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No. XIII.— ON THE DEPTH AND MAUINE DEPOSITS OF THE INDIAN 

 OCEAN, WITH DESCEIPTIONS OF THE DEPOSIT-SAMPLES COL- 

 LECTED BY Mr. J. STANLEY GAIIDINER IN 1905. 



By Sir John Murray, K.C.B., D.So., F.R.S., F.L.S., ^c. 

 (Plates 22-24.) 



Bead 17th June, 1909. 



THE INDIAN OCEAN. 



Historical. 



At the dawn of history the name " Erythraean Sea" was applied to what we now call the 

 Indian Ocean. The voyage of Nearchus, one of Alexander's generals, from the Indus to 

 the Persian Gulf is the first trustworthy record of a voyage in these seas. Two views 

 were held by ancient geographers as to the morphology of the Indian Ocean. According 

 to one view, supported by Eratosthenes and Straho, the Indian Ocean was connected 

 with the Atlantic to the south of Africa and with the general ocean which surrounds 

 the great land-masses. The upholders of this view evidently gave full credence to the 

 voyage of Necho as reported by Herodotus. About 610 B.C. this Egyptian monarch 

 sent ships manned by Phoenician sailors afloat on the Erythraean Sea with orders to 

 return by the south of Africa and the Pillars of Hercules to the Mediterranean. This 

 cruise was said to have taken three years. These early explorers related that in sailing 

 around the south of Africa they had the sun on their right hand, w^hich we know must 

 have been the case. Modern geographers are disposed to believe that this voyage was 

 not only possible, but that it actually took place as stated. The other view held by 

 ancient geographers, supported by Hipparchus and Ptolemy, regarded the Indian Ocean, 

 and also the Atlantic, as enclosed seas like the Mediterranean. Ptolemy's map repre- 

 sents the southern coast of Africa as running away to the east and connected by 

 unknown lands with the coasts of China. We now know that the former was the correct 

 view. 



About the beginning of the Christian era Hippalus, an Egyptian pilot, was the first 

 to observe the regular alternations in the direction of the monsoons of the Indian Ocean, 

 and to profit by them in opening up a route across the high seas from the Red Sea to 

 India. The shore routes were subsequently abandoned and a fresh impetus was given 

 to voyages to Oriental seas. In the ninth century the Arabs made frequent voyages to 

 the East. One Soleiman, from the Persian Gulf, is believed to have heen the first to 



SECOND SERIES. — ZOOLOGY, VOL. XIII. 48 



