OCEANOGRAPHICAL INVESTIGATIONS ii 



disclose two adjacent regions in which the bottom tern- Peculiar 

 peratures differed as much as 15° Fahr. (30^ Fahr. in the l-ondSonsTn 

 one region and 45 Fahr. in the other), and it was con- the Faroe 

 eluded that great masses of water at different temperatures ^^^""'^'• 

 were moving about, each in its particular course, maintaining 

 a remarkable system of oceanic circulation, and yet keeping 

 so distinct from one another that one hour's sail might be 

 sufficient to pass from the extreme of heat to the extreme of 

 cold. 



In 1869 Gwyn Jeffreys was associated with Carpenter and h.m.s. 

 Wyville Thomson in carrying on the work on board H.M.S. "i^o'cupme." 

 "Porcupine," which made three cruises: (i) to the west of carp'^nter, 

 Ireland, where dredgings down to 1470 fathoms were taken; and Thomson. 

 (2) to the Bay of Biscay, where dredgings were taken in depths 

 exceeding 2000 fathoms; and (3) to the Faroe Channel to 

 confirm and extend the "Lightning" observations. In 1870 

 the " Porcupine " carried on work in the Mediterranean and 

 the Strait of Gibraltar, which was continued in 1871 on board 

 H.M.S. "Shearwater." 



About the same time Leigh Smith made several voyages Leigh Smith. 

 to the Arctic regions, and, like Scoresby, recorded warmer layers 

 of water beneath the colder surface waters of the Arctic Ocean. ^ 



The researches briefly noticed in the preceding paragraphs The 

 paved the way for the special investigation of the physical, E^J^gdidon^'^ 

 chemical, and biological conditions of the great ocean basins 

 of the world carried out on board H.M.S. "Challenger" from 

 December 1872 to May 1876 by a staff of scientific observers. 

 During this period she circumnavigated the world, traversed 

 the great oceans in many directions, made observations in 

 nearly all departments of the physical and biological sciences, 

 and laid down the broad general foundations of the recent 

 science of oceanography. The results of the "Challenger" 

 Expedition were published by the British Government in fifty 

 quarto volumes, and became the starting-point for all subsequent 

 observations. 



Contemporaneous with the " Challenger " Expedition was The 

 that of the U.S.S. " Tuscarora," under Belknap, in the Pacific ^^'''^^^'°'^'^' 

 Ocean, which contributed greatly to our knowledge of the 



' Leigh Smith's temperature observations were pubhshed in Proc. Roy. Soc. Loud., vol. xxi. 

 pp. 94 and 97, 1873, and in Natural Science, vol. xi. p. 48, 1897. In the former paper Wells 

 (juotes a reading of 64° F. in 600 fathoms and a reading of 42° F. at 300 fathoms near Spitz- 

 bergen, and argues that they indicate the southward flow of a vast body of warm water from the 

 circumpolar region, while in the latter paper Leigh Smith refers to a warm undercurrent running 

 into the Arctic basin between Greenland and Spitzbergen. 



