MAGNETIC OBSERVATIONS. 73 



made there from 1840 to 1-846 (see Transact, of the Royal 

 Irish Academy, vol. xxii., pt. i., p. 74-96). 



1837. Sir David Brewster, A Treatise on Magnetism, p. 

 185-263. 



1837-1842. Sir Edward Belcher's Voyage to Singapore, 

 the Chinese Seas, and the western coasts of America (Phil. 

 Transact, for 1843, pt. ii., p. 113, 140-142). These observ- 

 ations of inclination, when compared with my own, which 

 were made at an earlier date, show a very unequal advance 

 of the curves. Thus, for instance, in 1803, I found the in- 

 clinations at Acapulco, Guayaquil, and Callao do Lima to 

 be +38 48', +10 42', and -9 54'; while Sir Edward 

 Belcher found +37 57', +9 1', and -9 54'. Can the 

 frequent earthquakes upon the Peruvian coasts exert a local 

 influence upon the phenomena which depend upon magnetic 

 force of the earth ? 



1838-1842. Charles Wilkes's Narrative of the United 

 States Exploring Expedition, vol. i., p. xxi. 



1838. Lieutenant James Sullivan's Voyage from Fal- 

 mouth to the Falkland Islands (Phil. Transact, for 1840, pt. 

 i., p. 129, 140-143). 



1838 and 1839. The establishment of magnetic stations 

 under the admirable superintendence of General Sabine in 

 both hemispheres, at the expense of the British government. 

 The instruments were dispatched in 1839, and the observa- 

 tions were begun at Toronto and in Van Diemen's Land in 

 1840, and at the Cape in 1841 (see Sir John Herschel in 

 the Quarterly Review, vol. Ixvi., 1840, p. 297 ; and Becque- 

 rcl, Traite d 1 Electricite et de Magnctisme, t. vi., p. 173). By 

 the careful and thorough elaboration of these valuable ob- 

 servations, which embrace all the elements or variations of 

 the magnetic activity of the earth, General Sabine, as super- 

 intendent of the Colonial observatories, discovered hitherto 

 unrecognized laws, and disclosed new views in relation to the 

 science of magnetism. The results of his investigations 

 were collected by himself in a long series of separate mem- 

 oirs (Contributions to Terrestrial Magnetism) in the Philo- 

 sophical Transactions of the Royal Society of London, and in 

 separate works, which constitute the basis of this portion of 

 the Cosmos. We will here indicate only a few of the most 

 important: (1) Observations on Days of unusual Magnetic Z>z's-_ 

 turbances (Storms) in the Years 1840 and 1841, p. 1-107; 

 and as a continuation of this treatise, Magnetic Storms from 

 1843-1845, in the Phil. Transact, for 1851, pt, i., p. 123- 



YOL. V D 



