HISTORY OF DISCOVERY RELATIVE TO MAGNETISM. 297 



"Wilke from observations Biade by Captains Cork and Fourneaux. One focus 

 of the ellipsis was designated as the stronger, the other as the weaker region. 

 Hausteen was induced to compare these statements with the observations, and 

 the comparison being satisfactory, he was led to investigate more tlioroughly 

 the theory of Halley, which, until then, he had looked upon as a wild specula- 

 tion. The result of these investigations was that he became a convert to the 

 theory of the existence of four movable magnetic poles. 



In 1811 the Royal Danish Society of Sciences had offered the annual prize 

 for the best answer to the question, "Whether it is necessary, in order to ex- 

 plain the magnetic phenomena of the earth, to admit the existence of several 

 magnetic axes, or whether one is sufficient?" At the beginning of the following- 

 year Hausteen presented the greatest part of his work, as far as it was com- 

 pleted, and the society crowned his labors with its principal prize. 



The most important part of Hansteen's work is that in which he treats of 

 the number, the position, and the motion of the magnetic poles. From all the 

 observations collected by him on the variations of the magnetic needle, he con- 

 cludes that there are four points ou the earth through which the lines of equal 

 deviation pass, viz., a stronger and a weaker one in the vicinity of each 

 geometric pole. Both the stronger poles, as well as the two weaker ones, are 

 situated opposite to each other, as if they were extreme points of the same axes. 

 All four have a regular rotation, the two northern ones from west to east, and 

 the southern ones from east to west. 



In order to elucidate the nature of the magnetism of the earth in each of its 

 relations, Hausteen also undertook to make numerous observations, and even 

 made a journey to Siberia, in order to carry on his investigations within the 

 region of greatest intensity of the magnetic phenomenon. This journey, besides 

 directly enriching our knowledge of the magnetism of the earth with valua- 

 ble results, had other consequences of great importance ; it called the attention 

 of the Russian government to this subject, and thus prepared the way for the 

 labors of Alexander von Humboldt, at whose request the Emperor of Russia, 

 with great liberality, ordered a number of magnetic observatories to be erected 

 in his empire. Humboldt, immediately after his return from his travels iu 

 America, (1799, 1S04,) had erected, iu a garden at Berlin, an observatory, ex- 

 clusively devoted to magnetism, and in which observations were made, often 

 from four to six consecutive days, every half hour without interruption. The 

 proposal of Humboldt, to erect similar observatories in other places of G-ermany, 

 was not responded to partly on account of the political disturbances which were 

 then visiting that country, partly because its celebrated citizen was intrusted 

 with a mission from his government to France, and was thus hindered, for the 

 time, in'the pursuit of his favorite object. Arago commenced in 1818, at Paris, 

 an exceedingly valuable series of magnetic observations, and by comparing them 

 with such as were made simultaneously at Kasan, he confirmed the assertion of 

 his friend Humboldt in regard to the importance and necessity of corresponding 

 observations. 



Humboldt returned to G-ermany in 1827, and established in the autumn of 

 1828 a continuous and regular series of observations. In consequence of his 

 solicitation, the Imperial Academy of St. Petersburg and the curator of the 

 University at Kasan, erected an observatory at St. Petersburg and Kasan, and 

 under the protection of the chief of the mining corps. Count Canain, magnetic 

 stations were established from the south of Russia through the whole of northern 

 Asia. The Russian Academy sent George Fuss to Pekin, where he erected 

 a magnetic observatory in the garden of the Greek convent, in which Kowanko 

 made a continued series of observations corresponding with those of all the 

 other stations. Admiral Greig also erected a magnetic observatory at Nico- 

 lajeff, in the Crimea ; and, at the instance of Humboldt, a subterranean mag- 

 netic station was established under the supervision of Professor Reich, in the 



