SCIENTIFIC ADVANTAGES OF AN ANTARCTIC EXPEDITION. 427 



This enormous ice slieet must have an important influence upon the 

 climatology of the whole world, and valuable information might be 

 obtained as to meteorological conditions through an Antarctic expedi- 

 tion. 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 coopera- 

 tion 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 geographical 

 survey of the Antarctic, one of the most urgent requirements of the 

 science of our earth. There are no measurements of the gravity con- 

 stant within the Antarctic region ; indeed, they are very scarce in the 

 Southern Hemisphere south of latitude 30° 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 observations 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 consideration, we may hope 

 for another important enlargement of the knowledge bearing upon the 

 connection between terrestrial magnetism and gravity. Gravity obser- 

 vations have been so much simplified of late, by Von Herack's ingen- 

 ious apparatus, 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 ques- 

 tion of the distribution of land within the South Polar region is closely 

 connected with it. The International Geodetic Permanent Commission 

 expressed it as their conviction 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 Eoss, no other observations of the values 

 of the magnetic elements have been made, we are perfectly ignorant of 

 the values of the secular variations south of latitude 50°, though this 

 information is urgently needed for the construction of trustworthy 

 magnetic charts required in navigation. Of the situation of the south- 

 ern 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 



