OF ARTS AND SCIENCES. 285 



made at places as remote as Toronto and Hobarton, and whicli both he 

 and Laniont afterwards extended to the magnetic inclination and inten- 

 sity, Ilansteen reaffirmed as the result of twenty-five years of observa- 

 tion in Christiania. Hansteen, however, changed the period from ten 

 years to 11.33 years. But the coincidence between this period and 

 that of the solar spots, with all its important inferences, still remains. 

 For Wolf, after a full discussion of 23,000 spots, observed between 

 1749 and 1860, has changed the spot-period from ten years, as origi- 

 nally derived by Schwabe from his own observations at Dessau be- 

 tween 1825 and 1850, to a little over eleven years. 



Fortunately for science, Hansteen's most important work was writ- 

 ten in the German language. But many of Iris papers are in his native 

 language, and are published in the journals of his own country, and on 

 this account are not generally accessible to scientific students. Never- 

 theless, his various contributions to " Schweigger's Journal," to the 

 "Annalen of Poggendorf," and to th.e " Astronomische Nachrichteu," 

 have made his name familiar and his merits widely known. Although 

 terrestrial magnetism gave the dominant key-note to the scientific 

 labors of his life, he published valuable researches in meteorology and 

 astronomy. 



In 1837 the Trigonometrical and Topographical Survey of Norway 

 was instituted, and Hansteen was placed at the head of it. In 1856 

 he completed the fiftieth year of his long term of service as a teacher 

 of science ; and his jubilee was duly honored, and a medal was struck 

 in commemoration of the event. In 1861 he retired from active labor. 

 Hansteen was elected in 1863 Foreign Honorary Member of this 

 Academy, in the place left vacant by the death of Biot. His merits 

 were early recognized by the Royal Society of London, and by the 

 Academies of Paris, Berlin, and St. Petersburg. 



The name of John Stuart Mill is so intimately associated with 

 most of the principal topics of modern philosophical discussion, and 

 with the gravest of open questions, with so many of the weightiest 

 subjects of unsettled theory and practice, that it would be diflacult to 

 say for which of his many works his fame is at present the greatest or 

 is most likely to endure. Those subjects in the treatment of which 

 the originality of his position was the least were those in which the 

 qualities most characteristic of him, and for which his writings have 

 been most esteemed, appear in clearest light. Unlike most other 

 great thinkers and masters of dialectics, he did not seek to dis- 

 play what his own invention had contributed to the arguments, or 



