GEOGRAPHICAL PROGRESS AND DISCOVERY. 



331 



gions of great productiveness and commercial 

 promise. The problem has changed from the 

 exploration to the commercial development of 

 Africa, as in Asia. 



THE OCEANS. In recent hydrographical sur- 

 veys contiguous areas with very different bot- 

 tom temperatures have been found in various 

 places. In every case the bottom layer in 

 both of the adjoining areas commences at the 

 same depth below the surface. The phenome- 

 non has been ascribed to submerged ridges of 

 land arresting the circulation of water between 

 the two areas. In the Wyville Thomson expe- 

 dition two such areas were found in the Faroe 

 Channel. An elaborate theory was advanced 

 of a wall of still water, separating the bodies 

 of different temperature, formed by the impact 

 of the Gulf Stream and the cold current from 

 the Spitzbergen seas. During the Challenger's 

 voyage the theory of submarine barriers was 

 advanced. The submerged ridge in the Faroe 

 Channel has been discovered by Murray and 

 Commander Tizard. It rises up within 200 

 fathoms of the surface, which is precisely the 

 depth at which the varying bottom tempera- 

 tures begin, the surface layer above the crest 

 of the ridge having the same temperature on 

 each side. The ridge, which is named after 

 Sir Wyville Thomson, rises 2,400 feet above 

 the bottom of the ocean. It is supposed to 

 be a glacial moraine. 



POLAR REGIONS. The ill-fated Jeannette, 

 which set sail from San Francisco July 8, 

 1879, under the command of Lieutenant De 

 Long, U. S. N., with the object of seeking an 

 entrance to the supposed open Polar Sea by 

 a northeast passage near Wrangel Land, 

 passed into the Arctic Ocean on August 29th. 

 The, ship entered the ice within sight of Wran- 

 gel and Herald Islands, which ice jammed 

 and shifted dangerously, causing the vessel to 

 spring a leak on January 10, 1880. Caught 

 in the pack, the vessel drifted to the north- 

 west. Bear, seal, and walrus were shot occa- 

 sionally. The ice was comparatively quiet 

 during the summer, but in October it began 

 to grind and pile. On May 16, 1881, land 

 was seen to the westward. This unknown 

 land was named Jeannette Island. On May 

 24th another island was in sight. It was 

 called Henrietta Island. A party landed on 

 this latter. It was from 2,000 to 2,500 feet 

 high, barren and rocky, with one large and 

 two smaller glaciers, and a covering of snow 

 and ice on the high parts from 50 to 100 feet 

 in thickness. Guillemots and murres nest- 

 ed in the cliffs in great numbers. The vege- 

 tation consisted only of lichens and mosses, 

 with one species of phanerogam. On the 

 9th the ice opened and left the vessel afloat, 

 and on the 12th it came together again and 

 crushed her. She had been under pressure 

 ever since she was first caught in the floe. 

 The boats and the greater part of the stores 

 and provisions were got out before the ship 

 went down. There were some 24 dogs, which 



could draw only the hospital-sled and a small 

 one with extra stores. The retreat on the ice 

 was directed toward the mouth of the Lena 

 by way of the New Siberian or Liakhov 

 Islands, which lay about midway in the course. 

 The position of the Jeannette when she sank 

 was about 600 miles from the Siberian coast, 

 in a direct line. For twenty-one months the 

 ship drifted helplessly with the pack, by the 

 action of the winds and the currents. For the 

 first five months after she was ice-locked off 

 Herald Island the motion of the ice was cy- 

 cloidal, the total result of the drift being only 

 45 miles. During the last six months the drift 

 was very rapid to the northwestward. The 

 soundings were 18 fathoms near Wrangel 

 Land. The greatest depth was 80 fathoms, 



LIEUTENANT GEOKGE W. DE LONG. 



the mean depth 35 fathoms. The Jeannette 

 became imbedded in the ice immediately after 

 entering the Arctic. No vessel could have 

 withstood the strain to which she was constant- 

 ly subjected for over eighteen months. In the 

 latter part of the drift the sea was very shallow, 

 20 fathoms or under. The bottom was blue mud. 

 Shrimps and numerous algse were brought up 

 in the dredges. The surface temperature of 

 the water was 20 above zero. The tempera- 

 ture of the air ranged from 58 below zero to 

 44 above. The mean temperature of the first 

 winter was 30 below zero, of the first summer 

 40 above zero. Heavy gales were not fre- 

 quent. The most violent shqwed a wind ve- 

 locity of 50 miles an hour. The fluctuations 

 of the barometer and of the thermometer were 

 moderate. Disturbances of the needle coin- 

 ciding with the auroras were observed. The 

 winter's formation of ice was 8 feet thick. The 



