114 Transactions. — Miscellaneous. 



similarly-conducted explorations of practically new fields of 

 inquiry, not only in the special departments of science 

 which came within the scope of the " Challenger" expedition, 

 but also in others of equal if not of greater practical im- 

 portance. It is well known that tlie solution of some of the 

 most intricate problems in various branches of scientific in- 

 quiry is at present impossible, in the absence of data that can 

 only be obtained by means of successful observations in 

 circum-polar regions, and more especially within the antarctic 

 area. Many of these problems have lately been discussed in 

 papers submitted to the greater scientific societies in England. 

 For example, we are told on the highest authority that it is 

 hopeless to strive with any prospect of success at the ad- 

 vancement of the theory of the earth's magnetism in the 

 complete absence of data from the Southern Hemisphere 

 beyond the 40th parallel. Those afforded by the magnetic 

 survey made by Sir James Eoss are no longer of any use for 

 that purpose, for it is well known that such changes have 

 taken place, since his time, in the magnetic elements south 

 of that parallel that nothing less than a new and complete 

 survey can supply the materials for properly revising the cur- 

 rent theory of the revolution of the magnetic poles. The 

 knowledge thus desired is of the greatest importance for the 

 practical requirements of navigation. Magnetic maps, based 

 on numerous direct observations, were calculated and drawn 

 by Gauss upwards of fifty years ago, and some of the most 

 eminent investigators in this branch of scientific inquiry have, 

 ever since his time, been engaged in attempts at reconstruct- 

 ing them so as to make them available for the whole globe ; 

 but all their efforts to do so have been obstructed by the 

 one insuperable obstacle — namely, want of knowledge of the 

 necessary elements within an area of not less than three 

 thousand five hundred miles in every direction from the south 

 pole, a want which cannot be supplied by any amount of 

 mathematical speculation. It is true that the Bureau des 

 Longitudes of France is at present engaged in the construction 

 of new magnetic maps, but it does not appear that their 

 labours have as yet extended far, or proved very successful. 

 It would seem that, in order to obtain a satisfactory general 

 magnetic map, observations should be made over all regions 

 as nearly as possible at the same time, and for this purpose 

 observatories, with a competent staff and a supply of similar 

 instruments for each, would be required at a considerable 

 number of places. With such aids it will be possible to make 

 practically simultaneous observations, and it may be hoped 

 that all the great maritime nations will unite in a general 

 effort to obtain them. Six of the expeditions appointed by 

 the Bureau have already started to their appointed stations, 



