Ixii NOTES. 



several successive nights, led me even then to express an earnest wish for the 

 employment of similar instruments, to the east and west of Berlin, to enable 

 us to distinguish between general phenomena and those which might belong 

 to local perturbations from the unequally heated crust of the Earth, or the 

 atmosphere in which clouds are formed. My departure for Paris, and the 

 long political troubles of Europe, prevented the accomplishment of my wishes 

 it that time. The light which, in 1820, the great discovery of Oersted threw 

 on the intimate connection between electricity and magnetism, excited, after a 

 'ong slumber, a general and lively interest in the periodical variations in the 

 Earth's electro-magnetic charge. Arago, who had began several years before 

 at the observatory at Paris, with an excellent declination apparatus of Gambey, 

 the longest uninterrupted series of hourly observations existing in Europe, shewed, 

 by the comparison with simultaneous perturbations at Kasan, the great advantage 

 which might be derived from such comparisons. "When I returned to Berlin, 

 after a residence of eighteen years in France, I had a small magnetic observa- 

 tory erected during the autumn of 1828, not only for the purpose of con- 

 tinuing the work which I had begun in 1806, but also and especially for the 

 purpose of instituting a series of simultaneous observations, at concerted hours, 

 at Berlin, Paris, and at Freiberg, at the depth of 216 feet below the surface. 

 The simultaneity of the perturbations, and the parallelism of the movements 

 for October and December, 1829, were represented graphically at the time 

 in Pogg. Ann. Bd. xix. S. 357, Tafel i. iii. An expedition, undertaken 

 under the orders of the Emperor of Russia, in 1829, to Northern Asia, gave 

 me an opportunity of carrying out my plan on a more extensive scale. It was 

 developed in the Report of a Commission specially appointed by the Imperial 

 Academy of Sciences ; and under the protection of Count Cancrin, Chef du 

 Corps des Mines, and the able direction of Professor Kupffer, magnetic stations 

 were established throughout Northern Asia, from Nicolaieff by Cathariuenburg, 

 Barnaul, and Nertchinsk, to Pekin. The year 1832, (Gottinger gelehrte 

 Anzeigen, S. 206), forms an epoch in the history of the science ; for it was 

 then that the illustrious founder of a general theory of terrestrial magnetism, 

 Friedrich Gauss, established in the Gottingen Astronomical Observatory 

 apparatus constructed on new principles. The magnetic observatory of 

 Gottingen was completed in 1834 ; and in the same year (Resultate der 

 Beob. des magnetischen Vereins im Jahr 1838, S. 135, und Poggend. Annalen, 

 Bd. xxxiii. S. 426), by the zealous and active assistance of an ingenious 

 physicist, "Wilhelm "Weber, Gauss's instruments and methods were made 

 known and brought into use throughout Italy, Sweden, and a large prrt ( 



