SCIENCE 



[N. S. Vol. XXXIV. No. 



phenomenon proves to be a regular feature, 

 which is, of course, still doubtful, it indicates 

 the existence of a counter current running to 

 the southwest. This may be the correct ex- 

 planation. But, as he cautions us, it re- 

 quires further investigation, especially, to test 

 its constancy. Vertical circulation, as well 

 as horizontal, may be playing its part here. 

 Current measurements at different depths 

 could not fail to yield valuable results. 



As a whole the intermediate waters proved 

 to be considerably colder in 1910 than they 

 were in 1873, differences as great as 5° C. 

 being observed, though the surface and the 

 deeper layers agreed fairly well wherever the 

 paths of the two expeditions approached each 

 other. Such periodic fluctuations are known 

 for the Norwegian Sea, but they offer a virgin 

 and most interesting field in the northwestern 

 Atlantic. 



The shallowness of the warm surface layer 

 in the western part of the Atlantic leads Dr. 

 Hjort to conclude that its cold bottom waters 

 come to it from the northwest; i. e., from 

 Baffins Bay. In this connection an examina- 

 tion of the Labrador current would be of 

 great value; as yet we know almost nothing 

 about the physical properties of the inter- 

 mediate waters north of, and at its meeting 

 with, the Gulf Stream, though its importance 

 as a surface phenomenon has long been recog- 

 nized. 



The character of this Arctic flow, and its 

 relationships to the Gulf Stream and to the 

 comparatively warm water along the western 

 shores of Greenland offer an attractive and 

 important field for oceanographic research, 

 one lying naturally at the doors of American 

 oceanographers. In such a study, current 

 measurements at different depths on and near 

 the Newfoundland banks would be of prime 

 importance. And that such can be made in 

 considerable depths has been proved by the 

 Michael Bars. 



A series of 70 current measurements were 

 made at eight different depths in the Straits 

 of Gibraltar, from the ship itself, in 200 

 fathoms. These show very clearly how the 

 inflow into the Mediterranean is limited to 



the upper 75 fathoms (about) while at its 

 height, with a velocity of about 1 m. per sec- 

 ond. On the other hand, when the outflow was 

 at its height the surface current was slight, 

 whereas the current into the Atlantic reached 

 the velocity of 2 m. per second. 



A second series of measurements off the 

 Azores show that there may be considerable 

 tidal currents, even as deep as 800 meters. 



The biological results are quite as important 

 as the oceanographic. With regard to the 

 finer plankton, the most important results are 

 that there is much more in coastal than in 

 oceanic waters, and that in oceanic waters the 

 maximum of vegetable plankton was at about 

 50 meters, less at the surface. 



By the time 100 meters was reached there 

 was only about one tenth as much as 50. Dr. 

 Hjort tells us that the different groups occupy 

 different bathymetric zones, the Peridiniae 

 nearest the surface, next the eoccoliths, and 

 deeper the diatoms. As to quantity, the liv- 

 ing plant cells are estimated at 3,000 to 12,000 

 per liter of sea water. 



The collection of the larger plankton, fishes, 

 crustaceans, etc., was very rich; and the 

 depth data were valuable, thanks to the method 

 of using the serial nets developed by Dr. Hjort. 

 For the details of the apparatus I must refer 

 the reader to Dr. Hjort's account; but, essen- 

 tially, it consisted in using a series of ten dif- 

 ferent horizontal nets simultaneously at each 

 station. It seems to me, as it did to Dr. 

 Hjort, that " provided that the catches were 

 large . . . the mere numbers would demon- 

 strate sufficiently convincingly at what d^th 

 the captures had been made." 



The data on the vertical occurrence of 

 fishes and crustaceans have proved to be most 

 valuable — they throw an entirely new light on 

 the whole subject. In the first place they 

 show very clearly that the intermediate fishes 

 and crustaceans are not homogeneous so far 

 as their bathymetric range is concerned, but 

 that species closely allied systematically may 

 differ in their distribution. Thus the fish 

 Cyclothone microdon and the prawn, Acanthe- 

 phyra muUispina, belong to a deeper zone 

 than their relatives C. signata and A. pur- 



