TERRESTRIAL MAGNETISM. ' 397 



Let us consider the North Pole first, the approximate position of 

 which we know best from observation. If one were aslvtnl to say exactly 

 where that pole has been in observation times, whether it has moved, 

 or where it now is, the answer must be, *■' 1 do not know.*" It is true 

 that Ross in 1831, by a single observation, considered that he had lixed 

 its position, and 1 believe hoisted the British flag over the spot, taking- 

 possession thereof; but he may or may not have set up his dip circle 

 over a position affected by serious magnetic disturbance, and therefore 

 we must still be donbtful of his complete success from a magnetic 

 point of view. Although eminent mathematicig-ns have calculated its 

 position, and Neumayer in 1885 gave a place to it on his charts of that 

 year, we have still to wait for observation to settle the question, for 

 one epoch at least. 



Happily, I am able to repeat the good news that the Norweijian^ 

 Capt. Koald Anuuidsen, sailed in June last with the express object of 

 making a magnetic survev of Ross's position and of the surrounding- 

 regions, in order to tix the position of the north magnetic pole. 

 Furnished with suitable instruments of the latest pattern, he proposes 

 to continue his investigations until 1905, when we may look for his 

 return and the fulfillment of our hopes. 



As far as we can now see, the south magnetic pole can not be 

 approached very nearly l)y the traveler, and we can only lay siege to it 

 by observing at stations some distance off, but encircling it. We have 

 our own expedition on one side of it, and now with the return of the 

 Gauss to South Africa in June last we have learned that that vessel 

 wintered in latitude 66^ 2' south, longitude 89° 48' east, a position on 

 the opposite side of the supposed site of the magnetic pole to that of 

 the Discovery. We may now pause to record our warm congratula- 

 tions to Doctor von Drygalski and his companions on their safe return, 

 accompanied by the welcome report that their expedition has proved 

 successful. 



In addition to the British and German expeditions, there are the 

 Swedish expedition and the Scottish expedition. Therefore, with so 

 many nationalities working in widely dift'erent localities surrounding 

 it, we have every reason to expect that the position of the south mag- 

 netic pole will be determined. 



THE SECULAll CHANOE. 



When, in the year 1600, Gilbert announced to the world that the 

 earth is a great magnet, he believed it to be a stable magnet; and it 

 was left to Gellibrand, some thirty-four years latei-. by his discovery of 

 the annual change of the magnetic declination near London, to show 

 that this could hardly be the case. Ever since then the i-emarkal)le and 

 unceasing changes in the magnetism of the(>arth have been the subject 

 of constant observation bv magneticians and of investigation h\ some 



