DEPTH OF THE PACIFIC. 17 



contestable and mucli contested hypothesis that the tides, instead of 

 formino- in a distinct manner in every basin of the ocean, have a 

 common origin in the great South Polar Sea, and roll towards the 

 north like one immense wave, in the double valley of the Atlantic* 



As to that part of the Pacific Ocean comprised between Japan and 

 the coasts of California, it is not by the swiftness of the propagation 

 of the tides, but by that of the earthquake- waves, that the mean 

 depth may be approximately estimated. In the terrible earthquake 

 of December 23rd, 1854, which partially destroyed several Japanese 

 towns, among others Yeddo and Simoda, the vibrations of the marine 

 surface traversed an oceanic space of 6,842 miles in 12 hours and a 

 few minutes ; and Prof. Franklin Bache was able to calculate, in 

 consequence, the swiftness of the waves and the depth of the ocean 

 across which they were propagated; this depth is an average of 

 2,342 fathoms.f Besides, various authentic soundings taken in the 

 northern basin of the Pacific between California and the Sandwich 

 XsL.nds, confirm the result of this calculation, since they indicate a 

 depth varying from 1,968 to 2,570 fathoms. Not far from the coast of 

 California 2,700 fathoms of depth have been found.:}: Between^ the 

 Philippine and the Marianne Islands two other soundings have given 

 3,267 and 3,609 fathoms, and even in this last operation the lead has 

 brought up specimens of the submarine soil, and 117 species of 

 minute forms of life. Finally, between the Pacific and the Indian Sea, 

 to the south of the East India Islands, Captain Pinggold found the 

 bottom more than 8^ miles below the surface. Thus one might throw 

 into this abyss of the sea, not only Pelion on Ossa but Gaourisankar 

 itself, the highest mountain of the globe ; and even if on its peak 

 Mont Blanc were set up, the summit of this colossus of the continent 

 of Europe would not reach to the surface of the water. 



The Indian Ocean, too, is probably very deep in the greater part of 

 its extent, but we only know those parts nearest land, and those in 

 hardly more than an approximate manner. Its gulfs, like those of the 

 Mediterranean and the Atlantic Ocean, have relatively a slight depth 

 of water : the Persian Gulf, for instance, having a mean depth of only 

 54, and the Red Sea of 163 to 273 fathoms. Those parts of the Gulf 

 of Bengal which are adjacent to the Coromandel Coast and the delta 

 of the Ganges, increase only very gradually in depth except near 

 the northern extremity of the Gulf, where a prodigious abyss has 



' * See below, the section entitled, The Tides. 

 t Report of the United States Coast survey. 

 X Sir John Herschel, Physical Geography, p. 39. 



