GENERAL DISCUSSION 



Just when the concept of the unity of all oceans 

 originated is not easy to ascertain. As soon as it 

 was recognized that the cold water in the depths of 

 the oceans had to come from Polar regions and that 

 the renewal of the supply of water in those regions 

 had to come from other latitudes, the idea of a world 

 ocean was born, and research was directed toward 

 both the circulation within and the exchange of 

 water between the different ocean basins. Appar- 

 ently the first one to undertake comprehensive 

 investigations in a systematic way was Alfred Merz, 

 who as long ago as 1922 initiated a card catalogue 

 of all hydrographic observations in all three oceans.' 

 These compilations were utilized in the preparation 

 of several articles by Wiist on both the Atlantic and 

 Pacific Oceans and one entitled "Meridionale 

 Schichtung und Tiefenzirkulation in den Westhalften 

 der drei Ozeane,"^ and another by Lotte Moller 

 on the Indian Ocean. Defant in a paper, "Die 

 systematische Erforschung des Weltmeeres,"^ pub- 

 lished four charts, two for the Atlantic, one for the 

 Pacific, and one for the Indian Ocean, on which 

 were shown the positions of the stations at which 

 vertical sections of temperature and salinity were 

 made in depths of 1,000 meters and in depths of 

 3,000 and more meters, according to records avail- 

 able at the Institut fur Meereskunde up to February 

 1, 1928, and he pubhshed lists of the sources of the 

 data. This chapter of the present volumes may be 

 regarded as an extension of the work initiated by 

 Merz, but several areas not covered by the charts 

 published by Defant have been added, viz., the 

 Norwegian, the Polar, and adjacent seas, the Medi- 

 terranean Sea, the Gulf of Mexico and the Caribbean 

 Sea, and the Red Sea. For various reasons it was 

 decided to omit the Bosporus and the Dardanelles 

 and the Black Sea. 



Regarding the Bosporus and Dardanelles, it will 

 be said that the Institut fur Meereskunde in Berhn 

 pubhshed in April 1928 "Alfred Merz Hydro- 



1 See article b y G. Wtist, this volume, p. 12. 



'i Conseil internat. Explor. Mer, Jour., vol. 5, pp. 7-21, 

 1930. The bibliography contains references to pertinent 

 literature. 



' Gesellsch. Erdkunde Berlin, Jubilaums-Sonderband, 

 1928, pp. 459-505, 1928. 



graphische Untersuchungen in Bospoms und Dar- 

 danellen," bearbeitet von Lotte Moller; Inst. 

 Meeresk. Veroffentl. Neue Folg., A., Geogr. natur- 

 wiss. Rhe., Heft 18. There are 284 pages of text 

 and a foho atlas of sixteen hthographed plates. 

 Merz made two expeditions himself, 1917 and 1918, 

 and he utilized the observations of others. Before 

 his death he had done much toward putting the 

 results into form for publication, but he did not 

 complete his manuscript. Profes.sor Moller finished 

 the report, and it was presented to the Gesellschaft 

 fur Erdkunde of Berlin on the One Hundredth 

 Anniversary of its founding "im Andenken an ihrem 

 unvergesslichen Vorstandsmitglied Alfred Merz, 

 gewddmet vom Institut fiir Meereskunde." 



During recent years the Russians have conducted 

 extensive investigations in the Black Sea. Ref- 

 erences to some papers on the work have been 

 found but they are very fragmentary. No complete 

 account of the work nor any synopsis or summary 

 of results has been available. To give references to 

 the few publications examined seems inadvisable. 



Some notes will be made on the utilization of 

 temperature and salinity in determining oceanic 

 circulation. The methods of modern djoiamical 

 oceanography rest primarily on the researches of 

 V. Bjerknes and V. W. Ek:nan, but the develop- 

 ments and elaborations by Helland-Hansen, Sand- 

 strom, Hesselberg and Sverdrup, and others, have 

 been invaluable in building up not only the princi- 

 ples but also the technique of practically applying 

 the principles. Two summaries of modern methods 

 will be mentioned. They are Albert Defant's 

 "Dynamische Ozeanographie"« and G. F. McEwen's 

 "A summary of baisic principles underlying modern 

 methods of dynamical oceanography."' 



Concurrently with increase in knowledge of the 

 physics of the sea and of the methods of utilizing 

 the physical facts derived from the sea in solving 

 problems of circulation, better plans for work at sea 

 have been formulated and there has been improve- 



* Einfiihrung in die Geophysik III, Berlin, verlag von 

 Julius Springer, 1929, pp. 222. 



«• Physics of the Earth, vol. 5, U. S. National Res. Council 

 Bull. 85, pp. 310-357, 1932. There are three pages of 

 bibliography. 



