424 



NATURE 



[March 3, 1898 



Ehrenberg), very few of the results of his labour in this 

 direction have been published. A better fate, I trust, awaits 

 the treasures that the hoped-for expedition will bring back ; for 

 so prolific is that ocean, that the naturalist need never be idle, 

 no, not even for one of the twenty-four hours of daylight 

 throughout an Antarctic summer, and I look to the results of a 

 comparison of the oceanic life of the Arctic and Antarctic 

 regions as the heralding of an epoch in the history of biology. 



The Practicability of Antarctic Exploration. 

 Dr. Nansen said a great Antarctic Expedition should be under- 

 taken by the British nation. He confined his observations to the 

 great importance of a land expedition in the Antarctic continent. 

 It would certainly be of the highest importance to have it in 

 connection with a naval expedition, which would afford an 

 excellent basis for such a land expedition. Dr. Murray had 

 already mentioned the possibilities, and perhaps probabilities, 

 that there was a large Antarctic continent covered by an ice- 

 cap. They did not quite know yet. It might be that there 

 were large islands, and there might be sounds in between covered 

 with floating ice. Whether that was so or not, it was certam 

 there must be one or several huge ice-caps inside this unknown 

 territory in the South, and he felt certain that the exploration of 

 these would give scientific information of the greatest importance. 

 There were many problems to solve, and the only place they 

 could try to solve them in was the polar regions. Green- 

 land had already given them much information about the ice- 

 sheet, but Greenland was too small, when compared with the 

 big ice-sheets in the glacial packs. They should look to the 

 much more extensive ice-sheets which they might find in the 

 unknown territory. He did not think it would be very difficult 

 to reach the Antarctic continent. They must remember they 

 knew a great deal more about ice investigation than in 

 the days of Ross. They had much better ships, and had 

 steam, and were not afraid to push the ships into an ice-pack. 

 They knew that if they were exposed to pressure and some 

 hard times, they had the means to get out of it again ; and his 

 opinion was that in the Southern sea they were surrounded by 

 much open water all round, and a ship would not run the risk of 

 being shut up in ice as long as in the Arctic regions, where the 

 seas were shut up by land round about. So far as he understood 

 it, they would not run so much risk in that way in the South as 

 in the Arctic. The ice generally opened in calm weather, and that 

 was exactly when sailing-vessels would not be able to make use of 

 the opportunity to get in. So he thought with their modern 

 steamships it would not be difficult to get into the Antarctic. 

 It had been said that the ice-sheet in the Antarctic con- 

 tinent was difficult to get at. It was difficult to ascend. Of 

 course, when they went along the Barrier, as Ross did, it was 

 difficult to get through, and probably the only way would be by 

 captive balloons. He believed captive balloons would be of the 

 greatest use for exploration in Polar regions. With regard to 

 the probable thickness of the ice-sheet in the Antarctic, some put 

 it at 2000 feet, some at 10,000 feet, but he would rather put it at 

 20,000 feet. The height might present considerable difficulty to 

 any land expedition. This enormous ice-sheet must have an im- 

 portant influence upon the climatology of the whole world, and 

 valuable information might be obtained as to meteorological 

 conditions through an Antarctic expedition. If such a great 

 naval expedition as had been suggested were sent from this 

 country, Norway would gladly join in the work and send out 

 another expedition to take part in the land work, and it would 

 be of the greatest importance if there could be international co- 

 operation in these expeditions, because simultaneous observations 

 could then be made in these Antarctic regions, and they could 

 lay their plans in a more scientific way. 



Dr. Neumayer on Gravity and Terrestrial 

 Magnetism. 

 A gravity survey is, in connection with a thorough geo- 

 graphical survey of the Antarctic, one of the most urgent re- 

 quirements of the science of our earth. There are no measure- 

 ments of the gravity constant within the Antarctic region ; 

 indeed, they are very scarce in the southern hemisphere south 

 of 30° lat. S., and they are so closely connected with the theory 

 of the figure of our earth that it is hardly possible to arrive at 

 any conclusive results in this all-important matter without ob- 

 servations within the Antarctic region. It is impossible to 

 foretell what effect an exact gravity survey in that region might 

 exert upon our views with regard to all physical elements 

 which depend upon the radius of our earth. Apart from that 



NO. 1479, VOL. 57] 



consideration, we may hope for another important enlargement 

 of the knowledge bearing upon the connection between ter- 

 restrial magnetism and gravity. Gravity observations have been 

 so much simplified of late, by von Herack's ingenious appa- 

 ratus, that it does not offer a serious difficulty to multiply 

 gravity determinations within the Antarctic region, so that we 

 may well be able to speak of a "gravity survey." The all- 

 important question of the distribution of land within the South 

 Polar region is closely connected with it. The International 

 Geodetic Permanent Commission expressed it as their convic- 

 tion that a gravity survey within that region would be of the 

 greatest benefit for higher geodetic theories. 



The probable connection between gravity and terrestrial 

 magnetism has already been referred to. But apart from this, 

 a magnetic survey of the Antarctic region is of the greatest 

 importance from other points of view. As, since the time of 

 Ross, no other observations of the values of the magnetic ele- 

 ments have been made, we are perfectly ignorant of the values 

 of the secular variations south of 50° lat, though this in- 

 formation is urgently needed for the construction of trustworthy 

 magnetic charts required in navigation. Of the situation of the 

 southern magnetic pole, and of its motion during the last fifty 

 years, we are equally ignorant, though the facts are so highly 

 important according to Gauss's theoretical deductions. 



Much as the mathematical theory of terrestrial magnetism 

 has been developed, of the physical theory of that mysterious 

 force in nature we are yet in perfect ignorance. This defect is 

 certainly to some considerable degree caused by the want of our 

 knowledge in higher latitudes. It seems as if the magnetic 

 character of the South Polar region is such as would afford all 

 facility for a sound investigation when compared with the mag- 

 netic conditions of the North Polar region. A glance at a 

 magnetic map shows how entirely different is the distribution of 

 the magnetic action in both polar regions. 



There is the interesting fact to be noticed in the south that the 

 two foci of total intensity are situated on the side towards the south 

 of the Australian continent, and nearly on the same meridian. 

 The magnetic action which makes itself manifest by magnetic 

 storms or disturbances reaches its highest degree likewise south 

 of the Australian continent, whereas to the south of South 

 America the storms become very scarce and of a similar magni- 

 tude to those in middle latitudes. This was most strikingly 

 proved by the observations in Orange Bay and South Georgia 

 during the period of international observations in 1882-83. Of 

 course the magnetic south pole and the situation of the foci 

 above mentioned, are in close connection with these facts, but 

 the reason of their distribution remains unexplained. A discussion 

 of all observations on southern polar lights also shows a con- 

 nection between their frequency and the maximum region of 

 magnetic disturbance. 



Though the examination of these few facts ought to prompt 

 the institution of a vigorous examination of the south polar 

 regions, the series is far from being exhausted : there is the 

 question of the geoid -deformation, the phenomena of the tides, 

 and the structure of the ice and its drifting. 



The resolution of the Sixth International Geographical Con- 

 gress that the present century should not be allowed to expire 

 without unveiling the mysteries of the south polar regions, ought 

 to be carried into effect. All scientific institutions and societies 

 trust that such will take place without any further delay. 



Sir Clements Markham on Antarctic Geography. 



I need scarcely say how fully I concur in every word that 

 has fallen from Dr. Murray on the subject of the scientific 

 results, and more especially of the geographical results of an 

 Antarctic Expedition. 



It is sufficient to point out the vast extent of the unknown 

 area, and that no area of like extent, on the surface of the earth, 

 ever -failed to yield results of practical, as well as of purely 

 scientific interest by its exploration. 



But there is much more to be said in the present instance : 

 because the little that we do know of the Antarctic regions points 

 unerringly to the very great importance and interest of the results 

 that are certain to attend further research. 



The ice barrier, discovered by Sir James Ross, is known to be 

 the source of the immense ice islands of the southern polar sea. 

 But it has only been seen for a distance of 300 miles. It requires 

 far more complete examination before any approach to an adequate 

 knowledge can be obtained, respecting the extent and nature of 

 the supposed ice- cap in its rear. 



