t COSMOS. 



" Carte de Tintensite magnetique horizontale entre Paris et 

 Naples," in the Mem. de VAcad. de Bruxelles, t. xiv ; the 

 observations of Forbes in Germany, Flanders, and Italy in 

 1832 and 1837 (Transact, of the Royal Soc. of Edinburgh, 

 vol. xv, p. 27) ; the extremely accurate observations of Biid- 

 berg in France, Germany, and Sweden, 1832 ; the observa- 

 tions of Dr. Bache (Director of the Coasts' Survey of the 

 United States), 1837 and 1840, at 21 stations both in refer- 

 ence to inclination and intensity. 



1806 1807. A long series of observations at Berlin ro 

 the horary variations of declination and the recurrence c 

 magnetic storms (perturbations) by Humboldt and Oltmannj 

 mainly at the periods of the solstices and equinoxes for [ 

 and 6, or even sometimes 9 days, and as many nights conse 

 cutively, by means of Prony's magnetic telescope which 

 allowed arcs of 7 or 8 seconds to be distinguished. 



1812. Morichini, of Borne, maintained that non-magnetic 

 steel-needles become magnetic by contact with the violet 

 rays of light. Regarding the long contention excited by this 

 assertion and the ingenious experiments of Mrs. Somer- 

 ville, together with the wholly negative results of Biess and 

 Moser, see Sir David Brewster, Treatise on Magnetism, 1837, 

 p. 48. 



-1 o-i f> i Q1 Q ~\ 



18<>3 18 9 6' i ^ e * wo c i rcumnav io a ti n voyages of Otto 

 von Kotzebue, the first in the Buric, the second, five years 

 later, in the Predprijatie. 



1817 1848. The series of great scientific maritime expe- 

 ditions equipped by the French Government, and which 

 yielded such rich results to our knowledge of terrestrial 

 magnetism ; beginning with Freycinet's voyage in the cor- 

 vette Uranie 1817 1820, and followed by Duperrey in the 

 frigate La Coquille 1822 1825, Bougainville in the frigate 

 Thetis 18241826, Dumont d'Urville in the Astrolabe 

 1826 1829, and to the south pole in the Zelee 18371840, 

 Jules De Blosseville to India 1828 (Herbert Asiat. Re- 

 searches, vol. xviii, p. 4, Humboldt, Asie Cent. t. iii, p. 468), 

 and to Iceland 1833, (Lottin, Voy. de la Recherche 1836, 

 pp. 376 409), du Petit Thouars with Tessan in the Venus 

 18371839, le Vaillant in the Bonite 18361837, the 

 voyage of the " Commission scientifique du Nord " (Lottin, 



