396 TERRESTRIAL MAGNETISM. 



were agreed upon for ()l)tainino- speciiil ohstM'vutioiis with them ;it the 

 same moment of (h'eenwich meiiii time. Both expeditions have suc- 

 cessfully completed this part of their intended work. 



To cooperate in like manner with these far southern stations, the 

 Argentine Government sent a special party of observers to Staten 

 Island, near Cape Horn, and the Germans another to Kerguelen Land, 

 whilst New Zealand entered heartily into the work. In additon, similar 

 observations were arranged to he made in certain British and colonial 

 observatories, which include Kew, Falmouth, Bombay. Mauritius, and 

 Melbourne; also in German and other foreign observatories. 



We have all read thrilling accounts of the journeys of the several 

 traveling parties which set out from the Discorery^ and of the immi- 

 nent dangers to life they encountered and how^ they happily escaped 

 them except one brave fellow named Vince. who disappeared over one 

 of those mighty ice cl ill's, upon which all Antarctic voyagers descant, 

 into the sea. In s})itc of all this there is a record of magnetic ol)ser- 

 vations taken on these joTiriK^ys of which oidy an outline has yet been 

 given. Anticipations of the value of these ohscr\ations are somewhat 

 clouded when we read in one report- that hills "more inland were com- 

 posed of granite rock, split and broken, as well as weatherworn, into 

 extraordinary shapes. The lower or more outer hills consisted of 

 quartz, etc., with basaltic dikes cutting through them.'' Conse- 

 (luently, we have to fear the etiects of local magnetic disturbances of 

 the needle in the land observations, while buoyed up with th(> hope 

 of obtaining normal results on board the ship. 



Judging from some land obs(n-vations which have' been received it 

 appears that considerable changes ha\'e taken place in the values of 

 the magnetic elements in the regions we are considering, but wdien 

 making comparisons w^e have to remember the sixty years which have 

 elapsed since Ross's time, and that he had nothing like the advantage 

 of steam for his ships, or of instruments of precision like our present 

 ship Dlscovrij. His ships also were, as we have already remarked, 

 much worse magnetically, causing far more serious disturbance of the 

 instruments. Hence the changes we note may not be entirely due to 

 changes in the earth's magnetism. 



The ()l)servations made by the officers of the Southern Cross at Cape 

 Adare in lSl>l»-l!t(»u also contribute to this ([uestion of magnetic change. 



THE MAGNETIC POLES OF THE EARTH. 



1 will noW' refer to those two areas on the globe where the dipping 

 needle stands vertically, known as the magnetic poles. The determina- 

 tion of the exact position of these areas is of great importance to 

 magnetic science, and I will just glance at what is being done to solve 

 the problem. 



