Oct. 15,1874] 



NATURE 



485 



theory the excess of loss of heat on the part of the Kam- 

 schatka current over that of the atmosphere, as stated 

 above, may be explained by attributing it to the cooling 



;Fic. 2.— Bed of the Pacific, Taiiaga Inland to tape Flattery. 



( effect of the counter-current beneath. It may here be 

 mentioned that the northernmost limit of the Japan 

 stream was 51° 12' N., long. 178° 20' E. 



The coincidence of observations on temperatures and 

 currents was very noteworthy. There was found, for in- 

 stance, at lat. 42° 51' N., long. 148° 14' E., a north-east 

 surface current of a half-knot per hour ; at 5 to 15 fathoms' 

 depth the temperature was 40-3° F., and in this space the 

 current was marked. In the next 5 fathoms the thermo- 

 meter fell (f, and correspondingly the current ceased to 

 be observable at this 20 fathoms' depth. At 200 fathoms 

 a steadily increasing current to the south-west was ob- 

 served ; while from 20 fathoms' depth all the way to the 

 bottom — upward of 4,000 fathoms — the fall of tempera- 

 ture was only 1°. A cold stratum of water was discovered, 

 coming down from Behring Straits as an under-current. 

 Between lats. 51-' and 52° and longs. 159" and i6g°, this 

 current is at 150 ft. below the surface, and itself of 400 ft. 

 depth. It was perceptible at lat. 42° 47' N., long. 148° 23 

 E., but south of that it disappears : lat. 51" 22' N., long. 

 162" 20' E. is believed to be nearly its centre. Now, at 

 the last-named location, at 22 fathoms, the thermometer 

 marked 357°; at 75 fathoms, 32' ; at 100 fathoms, 35-5°. 

 This current was again satisfactorily defined at lat. 51° 43' 

 N., long. 165° 25' E., and there the temperatures were, at 

 25 fathoms, 377° ; at 60 fathoms, 347° ; at 100 fathoms, 

 377". The bottom temperatures vary from 32° to 33'9''. 



Reviewing the results of the entire investigation in 

 respect to currents, the following deductions may be sum- 

 marised : — The Kuro .Sivva or Japan current extends on an 

 easterly course toward the American coast, its northern 

 limit nearly reaching the southern shores of Vancouver 

 Island ; and it passes down to the southward in what has 

 been incorrectly denominated the " California cold cur- 

 rent." Beneath this an under-current sets to the north- 

 west, and in lat. 50° reaches the surface, after which it 

 sets northward along the shores of British America and 

 the outstanding islands, thence gradually turns to the 

 westward, its direction being affected bytlie outline of the 

 coast, and exhibits at Sitka a strength of one knot per 

 hour and a northward ilow. In lat. 53° 30' N., long. 157° 

 \V., the current, to a depth of 5 fathoms, set to the south- 

 east, and this continued while observations were made 

 during sailing to the south-cast ; but between that posi- 

 tion and the line of the islands the current was to the 

 south-west, and close to the islands to the westward. It 

 is believed that a part of the water carried to the north- 

 west by the under-current, returns in long. 1 57" to the 

 northern portion of the Japan stream, and mingles with 

 it, returning to the southward along the western shores of 

 America, as part of the surface current ; and that the 

 part to the westward of long. 157° which sets toward the 

 south-west, passes as an under-current beneath the Japan 

 stream. A rapid fall in temperature — from 57° to 47" in 

 a few miles — in the Ounimak Pass, shows that the north- 

 west shores of the Aleutian Islands are washed by the 

 cold ISehring Straits current, which is somewhat modilred 

 in temperature by the inflow of part of the westerly 

 current from the eastward of the islands. 



Many observations were made which indicated the 

 relation of prevailing winds to surface currents. The 

 material obtained from the sea bottom off the Kurile 

 Islands had, in addition to the usual ooze, greyish-black 

 sand, gravel, and lumps of lava. Similar sand and gravel 

 were found, and also sponge, in the neighbourhood of the 

 Aleutian Islands. The northern route for a telegraph 

 cable, as finally indicated by this survey, is 4,200 miles in 

 length ; the southern, about 6,000 miles. The former 

 route will present great though probably not insuperable 

 difficulties, such as that of the sudden declivity off the 

 Aleutian Islands, the frequent fogs which made even the 

 survey tedious, the embarrassments incident to a northern 

 region, where there are few of the means provided on more 

 civilised shores to meet the requirements of working 

 parties and occasional repairs. The chief merits of the 

 northern route are its comparative shortness and its pro- 

 pinquity to United States territory. 



