TERKESTRIAL MAGNETISM. 73 



founded on Erman's observations, in the Report of the 

 Committee of Physics of the Royal Society on the occasion 

 of the Antarctic Expedition, 1840, Plate iii.) 



1828 1829. Humboldt' s continuation of the observa- 

 tions at the solstices and equinoxes with a Gambey's needle 

 on horary variation and extraordinary perturbations, begun 

 in 1800 and 1807 in a magnetic house built expressly 

 for the purpose at Berlin. Corresponding determinations 

 made at Petersburg, NikolajefF, and in the mines at 

 Ereiberg, by Professor Reich, at 216 feet below the surface. 

 Dove and Biess continued these observations until Nov. 

 1830, including both declination and intensity of the hori- 

 zontal force. (Poggend. Annalen, Bd. xv. S. 318 336 ; 

 Bd. xix. S. 375391, with 16 Tables; Bd. xx. S. 545 

 555.) 



18291834. The botanist David Douglas, who was 

 killed at Owyhee by falling into a pit into which a wild bull 

 had previously fallen, made a fine series of magnetic obser- 

 vations on the north-west coast of America and in the 

 Sandwich Islands, including one station on the edge of the 

 crater of Kiraueah (Sabine, at the British Association 

 Meeting at Liverpool, p. 27 32). 



1829. Kupffer, Voyage au Mont Elbrouz dans le Cau- 

 case (p. 68 and 1]5). 



1829. Humboldt, observations on terrestrial magnetism, 

 together with astronomical determinations of geographical 

 position, on a journey by command of the Emperor Nicholas 

 in Northern Asia, from the long, of 11 3' to that of 

 80 12' east of Paris, near Lake Dzaisan, and from the lat. 

 of 15 43' (in the Island of Birutschicassa in the Caspian) to 



