REPORT ON OCEANIC CIRCULATION. 
3 
rainfall is large, are India, the winds arriving there having really traversed the ocean 
from near latitude 30° S.; the United States, the winds arriving there after having 
traversed nearly the whole breadth of the Atlantic and the Gulf of Mexico ; and more 
particularly China and Japan, on which coasts the winds arrive after having traversed 
more than half the breadth of the Pacific, The numerous East India islands scattered 
over the Western Pacific very largely, in proportion to their mountainous character, 
increase the rainfall, especially in the equatorial region. This greatly reduces the 
specific gravity of the surface waters, which, in turn, has important bearings on the 
distribution of deep-sea temperatures in the respective regions. The West India 
Islands have a similar influence in lowering the specific gravity of the surface over that 
portion of the Atlantic. On the east coast of South America the winds blow directly 
home on the continent, but, as they cross no extensive island groups on their way, the 
specific gravity of the sea is not reduced, as happens off the south-east coast of Asia. 
But to the south of Monte Video the prevailing winds are no longer from the sea, but 
they blow from the land seawards, being within the large region swept by the north¬ 
westerly winds of the southern hemisphere ; and, as will appear farther on, with 
marked dissimilar effects on the temperature and specific gravity of the ocean off 
these coasts. 1 
1 The temperature observations utilised in preparing the maps which accompany this Report are noted below : — 
1. Report on the Deep-Sea Temperature Observations obtained by the Officers of H.M.S. Challenger, during the 
years'1873-76 (Phys. Chem. Chall. Exp., pt. iii., 1884). 
2. Preliminary Report of the Scientific Exploration of the Deep Sea in H.M. Surveying-vessel “ Porcupine,” 
during the summer of 1869, conducted by Dr Carpenter, V.P.R.S., Mr J. Gwyn Jeffreys, F.R.S., and Prof. Wyville 
Thomson, LL.D., F.R.S. ( Proc. Roy. Soc., vol. xviii. p. 397, 1869). 
3. Report on Scientific Researches carried on during August, September, and October 1871 in H.M. Surveying 
Ship “Shearwater,” by William Carpenter, M.D., LL.D., F.R.S. (Proc. Roy. Soc., vol. xx. p. 535, 1871). 
4. The Annual Lists of Oceanic Depths and Serial Temperature Observations of the Hydrographic Department, 
Admiralty, London. In addition to these, Captain Wharton, the hydrograplrer, placed at my service all the 
unpublished data in the hydrographic office. 
5. The Norwegian North Atlantic Expedition, 1876-78: the North Ocean, its Depths, Temperature, and 
Circulation, by Prof. H. Mohn, Christiania, 1887. 
6. Three Cruises of the United States Coast and Geodetic Survey Steamer “Blake,” in the Gulf of Mexico, in the 
Caribbean Sea, and along the Atlantic Coast of the United States from 1877 to 1880, by Alexander Agassiz, Boston and 
New York, 1888 (Bull. Mus. Comp. Zool., vols. xiv. and xv.). 
7. Reports on the Dredging Operations off the West Coast of Central America to the Galapagos, to the West of 
Mexico, and in the Gulf of California, in charge of Alexander Agassiz, carried on by the U.S. Fish Commission 
Steamer “Albatross,” Lieut.-Commander Z. L. Tanner, U.S.N., commanding (Bull. Mus. Comp. Zool., vol. xxiii. p. 1, 1892). 
8. Deep-sea Sounding and Serial Temperatures in the North Pacific Ocean, obtained 1873-74 in the United States 
Steamer “Tuscarora,” Commander George E. Balknap, Washington, 1874. 
9. Report of the Results of the Survey for the purpose of determining the practicability of laying a Telegraphic 
Cable between the United States and the Hawaiian Islands, Washington, Government Printing Office, 1892. 
10. The Exploration of the Gulf of Guinea, by J. Y. Buchanan (Scot. Geogr. Mag., vol. iv. pp. 177 and 233, 1888). 
11. Deep-sea Sounding: a Brief Account of the Work done by the U.S.S. “ Enterprise ” in Deep-sea Sounding 
during 1883-86, by Captain A. S. Barker, U.S.N., New York, 1892. 
12. Journal of Hydrological Observations made by the Officers of the Corvette “Vitiaz” during a voyage of 
Circumnavigation, 1886-89, by Admiral S. Makaroff, Admiralty, St Petersburg. (The proof sheets of the forth¬ 
coming volume of the Cruise of the “ Vitiaz” have been kindly forwarded by Admiral Makaroff with permission to use 
the observations in this investigation). 
13. Berichte der Commission fur Erforschung des ostlichen Mittelmeeres, Zweite Reihe (Denkschr. d. K. Akcid. 
Wiss. Wien, Bd. lx.). 
