410 Proceedings of the Royal Physical Society. 



netic force of the Old World (the weaker of the two), lies 

 a good many degrees farther north than that of the New 

 World. 



Another fact, which is rather a puzzling one, is the very 

 great relative proportion of metallic falls which have been 

 discovered in America, as compared with any other part of the 

 known world — thirty-two meteoric irons having been found 

 in the United States, according to Professor Shepard, twenty- 

 three of which are included in his meteoric zone. While 

 only fourteen meteoric irons (whose time of fall is unknown) 

 have been recorded as found in the Old World, and eleven of 

 these falls are included in its so-called meteoric zone.* Mr 

 Greg gives the number of localities of meteoric irons in the 

 Western Hemisphere as fifty-seven ; those of the Eastern 

 Hemisphere being twenty-seven. f Various explanations have 

 been given of these facts ; it is rather curious, however, 

 to observe, that in the New World, we have the greatest 

 number of metallic falls, apparently in the neighbourhood of 

 the very locality where the magnetic force is described as 

 being in a maximum in the northern hemisphere. The 

 metallic falls of the Old World seem also to bear a rela- 

 tion to the other northern magnetic pole ; though, from its 

 force of attraction being relatively weaker, it may be, the 

 number of these metallic aerolites here is less, and the con- 

 centration of them together would also appear to be less ; the 

 meteorites straggling, in their deposition, to greater distances 

 from its centre, and so adding to the apparent length of this 

 so-called meteoric zone. Can these various circumstances be 

 dependent simply on an accidental coincidence % or do they 

 not, at least at first sight, suggest the idea that this strange 

 agent of magnetism has really something to do with these 

 peculiar arrangements \ 



Writers on terrestrial magnetism tell us, as one of the 

 ascertained results of their labours, that the agents of the 

 greater part of the magnetic force of the earth are situated 

 exclusively in the interior of the earth, although minor mag- 

 netic oscillations and influences on its surface are due, without 

 doubt, to the direct magnetic influence of the sun and moon ; 



* American Journal of Science, 1850. t Essay on Meteorites, 1855.. 



