CXX NOTES. 



( 511 ) p. 331. Kosmos, Bd. i. S. 194 und 435, Anm. 31 and 32 , Engl. 

 trans. Vol. i. p. 176, Notes 161 and 162. 



( 512 ) p. 332. The first observations of the kind were made on the tower of the 

 Augustine's church, at Mantua (1590.) Grimaldi and Gassendi were acquainted 

 with similar instances, all in geographical latitudes where the inclination of 

 the magnetic needle is very considerable. On the subject of the first measure- 

 ments of the magnetic intensity by the oscillation of a needle, compare my 

 Relation hist. T. i. pp. 260264, and Kosmos, Bd. i. S. 432434 (Engl. 

 transl. Vol. i. Note 159). 



( 513 ) p. 334. Kosmos, Bd. i. S. 436439, Anm. 36 (Engl. tram. Vol. i. 

 Note 166). 



( 4 ) p. 334. Kosmos, Bd. i. S. 189 (Engl. trans. Vol. i. p. 171.) 

 ( 514 bis) p. 335. [Additional note ly the Editor. The desire so earnestly 

 expressed by the author in the text, pp. 334 and 335, that " the laws of ter- 

 restrial magnetism should be thoroughly sought out by naval expeditions, 

 which should examine, as nearly as possible at the same time the state of 

 magnetism over all the accessible parts of the globe which are covered by the 

 ocean," that " such expeditions should be combined with land surveys," and 

 that " the year 1850 might deserve to be marked as the first normal epoch in 

 which the materials of a magnetic map of the world should be assembled," 

 is much nearer its fulfilment than M. de Humboldt seems to have been 

 aware of when the second volume of Kosmos was published in Germany 

 (October 1847). The antarctic expedition of Sir James Clark Ross, referred 

 to in the text, has been followed by that of Lieuts. Moore, R.N. and Clerk, 

 Royal Artillery (1845), by which the magnetic survey of the accessible por- 

 tions of the high latitudes of the southern hemisphere has been completed ; 

 by the voyages of Lieuts. Smith and Dayman, R.N. (1844 and 1845) between 

 the Cape of Good Hope and Van Diemen Island ; of Lieut. Moore, R.N. (1846) 

 to Hudson's Bay; and by the land expedition of Lieut. Lefroy, Royal 

 Artillery (1843-44), by which the whole of British North America east of the 

 Rocky Mountains, from the frontiers of the United States to the shores of 

 Hudson's Bay and the Polar ocean, has been magnetically surveyed. These 

 were all special surveys, undertaken by the British Government expressly for 

 the magnetical purposes which they accomplished ; and, with the exception of 

 the observations in Lieutenant Moore's voyage to Hudson's Bay, which are now 

 (February 1848) in process of reduction, their results have been deduced and 

 published. In addition to special expeditions to parts of the globe which are 

 either remote or difficult of access, the British Government has availed itself 



