34 J 



NATURE 



[Atigust 9, 1 8 S3 



movement probably continues during a long period of 

 time. It may be on the whole gradual and impercepti- 

 ble ; but if, from time to time, the roofs of the huge 

 vesicles, whence lava and steam have escaped, should 

 give way, though there may be no perceptible change of 

 level at the surface, such shocks will be generated as to 

 convulse the area with earthquakes. We may infer that 

 the Ischian earthquakes, though not directly connected 

 with the present active volcanic phenomena of the 

 district, are the result of the former extravasation of 

 volcanic materials, and the consequent vesicular condi- 

 tion of the earth's crust at the locality. But we must 

 await the careful collection of evidence before any posi- 

 tive conclusion on the subject can be embraced. 



THE NORWEGIAN NORTH-SEA EXPEDITION 



WITH the general work of the expedition sent out by 

 the Norwegian Government in 1876-8 for the in- 

 vestigation of the physical and biological conditions of 

 the North Atlantic, our readers have already been made 

 familiar by communications from Dr. Mohn during the 

 progress of the expedition. We have, moreover, already 

 noticed one or two of the five volumes containing some 

 of the results of the expedition. When the series of 

 publications connected with the expedition is complete, 

 it will form one of the most important contributions to a 

 knowledge of the deep sea hitherto published. The 

 present article is concerned with vols. iv. and v. of the 

 series, containing a historical account of the expedition, 

 a description of the apparatus used, the astronomical, 

 magnetic, geographical, and natural history observations. 

 The historical account by Capt. Wille, who was in 

 command of the vessel, the Voringen, tells us that so long 

 ago as 1874 Professors Mohn and G. O. Sars memorial- 

 ised the Norwegian Government on the importance of a 

 thorough investigation of the North Atlantic. In the me- 

 morial we find an excellent summary of what had already 

 been done by previous expeditions, and what might be ac- 

 complished by a new one. The Norwegian Government 

 entered heartily into the proposal for an expedition, and 

 after taking competent advice in the matter, resolved to 

 agree to the prayer of the memorial, and appointed Capt 

 Wille to make the necessary preparations. Capt. Wille 

 at once proceeded to England to confer with Sir George 

 Nares, and to purchase apparatus. A suitable vessel, 

 the Voringen, was purchased, and specially fitted and 

 equipped for the work of the expedition ; very brief and 

 elastic instructions were issued for the general conduct 

 of the expedition, while each member of the comprehen- 

 sive scientific staff was furnished with special instructions 

 for guidance in his work. The liberal scale on which the 

 expedition was organised has guided the Norwegian 

 Government in the publication of the results. These are 

 contained in a series of large quarto volumes, beautifully 

 printed (in Norwegian and English), and abounding with 

 maps, coloured illustrations, and engravings. These 

 volumes are liberally distributed among institutions and 

 individuals in all countries, wherever indeed they are 

 likely to be of service to science. Such liberality in a 

 comparatively poor Government like that of Norway is in 

 marked contrast to the conduct of the Government of the 

 wealthiest country in the world in respect of the Chal- 

 lenger publications. 



The general scope of the expedition was (1) to deter- 

 mine by soundings the contour of the sea-bed ; (2) the 

 rate and direction of currents ; (3) the surface-tempera- 

 ture of the sea ; (4) to investigate the physical conditions 

 and chemical constituents of the sea- water ; (5) zoological 

 work ; (6) botanical work ; (7) meteorological observa- 

 tions ; (8) magnetical observations ; (9) whatever other 

 observations time and place might render practical. 

 Thus it will be seen the programme was comprehensive 

 enough ; and as the voluminous reports show, much 



valuable work was done in each department. Among 

 the scientific staff on board were Prof. Mohn and G. O. 

 Sars. 



The Voringen prosecuted her work for about three 

 months in the summers of the years 1876-7-8. During 



.'I -'Will 



km 



1 



that time she made numerous sections over the region 

 lying between the west coast of Norway and a line 

 extending from Iceland to Spitzbergen on the one side, 

 and between Faeroe and the north of Spitzbergen on the 

 other; in 1878 moreover she made a circuit east and 



