1 86 



NATURE 



[October 6, 192 1 



leader of the expedition. Below deck are 

 the cabins of the scientific staff, and store-rooms 

 for the various instruments, fishing gears, col- 

 lections, etc. The winches are worked by steam. 

 A big trawl-winch placed forward has two 

 drums, the smaller carrying 4000 metres of 

 steel-wire 14 mm. in diameter for trawling 

 at moderate depths, and the larger, carrying 

 10,000 metres of steel-wire tapering from 14 mm. 

 to 7 mm. in diameter, to be used for greater 

 depths. The three winches for vertical hauls 

 (water-bottles, plankton nets, and sounding) are 

 placed on the port side of the ship ; one works the 

 Lucas sounding machine and a drum carrying 

 6000 metres of phosphor-bronze wire ; another is 

 a small hand-winch to be used for the surface 

 layers ; and the third works a big drum carrying 

 10,000 metres of steel-wire 4 mm. in diameter. 

 The steel-wire ropes have been supplied by 

 Messrs. Craven and Speeding Bros., Sunderland, 

 and the hydrographical instru- 

 ments by the Laboratoire Hydro- 

 graphique, Copenhagen, of which 

 Prof. Martin Knudsen is director. 



The personnel of the expedition 

 is as follows : — Dr. Jobs. 

 Schmidt, leader of the expedition ; 

 Dr. J. N. Nielsen (Meteorological 

 Institute, Copenhagen), hydro- 

 grapher ; P. Jespersen and A. V. 

 Taaning (Danish Committee for 

 the Study of the Sea) ; K, 

 Stephensen (Zoological Museum, 

 Copenhagen) ; J. Olsen (Poly- 

 technic College, Copenhagen), 

 assistant hydrographer. N. C. 

 Andersen, ship's doctor, will also 

 take part in the investigations. 

 Prpf. C. H. Ostenfeld expects to 

 join the expedition later on 

 during its stay in West Indian 

 waters. 



The Dana, is under the 

 command of Capt. G. Hansen, 

 who served for many years as captain of the 

 research steamer Thor. 



Further particulars of the expedition are given 

 in the subjoined resume of a lecture delivered by 

 Dr. Jobs. Schmidt at the meeting of the Inter- 

 national Council for the Exploration of the Sea at 

 Copenhagen in July last. 



The object of the expedition is to study the oceano- 

 graphical conditions of the open North Atlantic Ocean. 

 By oceanographical conditions is meant not only the 

 physical, but also the biological conditions of ^ the 

 ocean, and in combining investigations of both It is 

 hoped to obtain some Insight Into the problems of the 

 relation of the biology of the ocean to some of the 

 physical factors which It will be possible to trace. 

 The principal aim, therefore, is of a very general 

 nature. There are In addition, however, some tasks 

 of a more special nature, the most important of 

 which is an Investigation of the oceanic portions 

 of the life-histories of the common eel and the 

 conger ; further, the biology of other oceanic fishes, 



NO. 2710, VOL. 108] 



such as the various large scomberoids, dolphins, 

 sword-fishes, sun-fishes, flying-fishes, and others, will 

 be studied. 



We know too little about the general biology of the 

 ocean to be able to do our -vyork from biological points 

 of view alone ; it has therefore been considered wiser 

 to allow hydrographical views to dictate the course of 

 the expedition. To put it briefly, we shall work 

 biologically at each hydrographical station. 



We do not expect to be able to pay much attention 

 to the bottom of the ocean and its fauna; this 

 would require more time than we have at our 

 disposal. On the other hand, we shall try to concen- 

 trate our efforts on a study of the water-mass itself, 

 which on an average has a depth of about 4000 metres 

 in the North Atlantic. Our plan is to investigate not 

 only the upper water layers, but also the intermediate 

 layers and those covering the bottom, and we Intend 

 to do this in regard to their temperature, salinity, 

 and gas-content, and also their fauna. Afterwards 

 we shall compare the data we have obtained in this 

 way in order to try to understand something of the 

 phvsical factors which control the occurrence of the 



Fig. 2. — Planned routes of the Dana Expedition, 1921-22. 



various pelagic communities of animals and plants, 

 in regard to both their horizontal and vertical dis- 

 tribution. If possible, we shall pay special attention 

 to the fauna of the deeper and deepest water layers 

 of the ocean. 



A current-chart of the North Atlantic shows that 

 the most conspicuous feature is the great anticyclonic 

 rotation of the superficial water-masses with the Sar- 

 gasso Sea forming, so to speak, a centre of the rota- 

 tion. Our plan is to investigate this great anti- 

 cvclonlc system, and we propose to do It by means 

 of several cross-sections radiating from the centre, 

 the Sargasso Sea, which, in more than one respect, 

 will be our principal field of work (Fig. 2). 



First, there is the inflow of water from the South 

 Atlantic and the south equatorial current, which 

 passes the boundary between the North and South 

 Atlantic joining the current system of the North 

 Atlantic. We propose to investigate carefully this 

 boundary region between the North and South 

 Atlantic, and we shall do this by means of a section 

 between Africa and Brazil about the region where the 

 Atlantic Ocean Is narrowest. Through this section 



