IV DEPTHS AND DEPOSITS OF THE OCEAN 131 



Lambert's equal-surface projection, one to show the Atlantic Equai-smface 

 Ocean, one the Pacific, and one the Indian Ocean, on which all hemShSes. 

 the soundings recorded up to that time, in depths exceeding 

 1000 fathoms, were laid down in position, and contour-lines of 

 depth drawn in. Since then these hemispheres have been kept 

 up to date by Dr. Bartholomew by the inclusion from time to 

 time of new soundings recorded in depths greater than 1000 

 fathoms, and the contour-lines have been redrawn. The North 

 Atlantic from one of these hemispheres is shown on Map III., 

 where practically all soundings recorded in depths greater than 

 1000 fathoms are placed in position, the two last figures being 

 omitted. 



The total number of soundings laid down on these charts Number of 

 is 5969, of which 2500 are in the Atlantic (1873 in the North l^^'^t^l^eater 

 Atlantic and 627 in the South Atlantic), 2466 in the Pacific than 1000 

 (1266 in the North Pacific and 1200 in the South Pacific), and f^^^"'^'- 

 1003 in the Indian Ocean. These figures show that pro- 

 portionately a great many more soundings have been taken 

 in the Atlantic than in the Pacific, which covers an area so 

 much larger. Of these 5969 soundings, 2516 were taken in 

 depths between 1000 and 2000 fathoms, 2962 in depths between 

 2000 and 3000 fathoms, and only 491 are laid down in depths 

 exceeding 3000 fathoms, of which 46 exceed 4000 fathoms, and 

 only 4 exceed 5000 fathoms. It may be added that though only 

 four soundings over 5000 fathoms have been laid down on the 

 charts, in reality seven have been recorded, three in the South 

 Pacific in the Aldrich Deep, and the other four taken by the 

 U.S.S. "Nero" in the Challenger Deep in the North Pacific, 

 near the island of Guam, but in such close proximity to one 

 another that only the deepest, 5269 fathoms, could be laid down 

 on the map. 



The deepest sounding hitherto recorded is that of 5269 Deepest 

 fathoms just mentioned. • This is equal to 9636 metres, or ^oundini. 

 31,614 feet, or 66 feet less than six English miles, and it exceeds 

 the greatest known height above the level of the sea (Mount 

 Everest in the Himalaya Mountains, 29,002 feet) by 2612 feet. 

 The known range of variation in the level of the earth's crust, Range of 

 from the greatest height above sea-level to the greatest depth i^'evd of'the^ 

 below sea-level, is thus 60,616 feet, or about ii|- English miles, earth's cmst. 

 but this range is very small when we remember that the 

 diameter of the earth is nearly 8000 miles ; in fact, on a six-feet 

 globe a mere scratch one-tenth of an inch deep would represent 

 the extreme variation in the irregularities of the earth's surface. 



