1821.] Historical Sketch of Electro-magnetism. 195 



t, t, x. Some part, perhaps, of the os ilium 1 

 y, z. Perhaps one of the processes of the cross-bone (kreuz- 

 bein). 



Figure 10. 



i, n, in, iv, v. Vertebrae probably of the back, i appears to 

 have been the foremost ; v the hindermost, since v resembles 

 more in its shape the other vertebrae of the ribs. 



s, s, s, s, s. Five lateral processes of the right side. 



1, 2, to 8. Fragments of eight ribs. 



Article V. 



Historical Sketch of Electro-magnetism. 

 (To the Editor of the Annals of Philosophy.) 

 SIR, 



Having been engaged latterly in looking over the various 

 papers that have been written on the subject of electro-magnetism, 

 1 found much difficulty in gaining a clear idea of what had been 

 done, and by whom, in consequence of their s;reat variety, the 

 number of theories advanced in them, their confused dates, and 

 other circumstances. This induced me to draw up a catalogue 

 of such of these papers as I could obtain access to, and to make 

 some general arrangement of the matter contained in them. The 

 following attempt does not by any means profess to give a correct 

 view of the subject, or of what has been done in it ; nevertheless, 

 perhaps, in the absence of a digested and scientific account, you 

 may think it worth publication. Though it can give no informa- 

 tion to those who have worked in the field that has been opened 

 by this new discovery, it may assist in informing others what the 

 labourers have done ; and after knowledge has been acquired, it 

 is always desirable that it should be distributed. 



M. Oersted, Professor of Natural Philosophy, and Secretary 

 to the Royal Society, of Copenhagen, has, for many years, been 

 engaged in inquiries respecting the identity of chemical, electri- 

 cal, and magnetic forces ; and as early as 1807 proposed to try 

 " whether electricity the most latent had any action on the mag- 

 net." At that time no experimental proofs of the peculiar 

 opinions he entertained were known ; but his constancy in the 

 pursuit of his subject, both by reasoning and experiment, was 

 well rewarded in the winter of 1819 by the discovery of a fact 

 of which not a single person beside himself had the slightest 

 suspicion; but which, when once known, instantly drew the 

 attention of all those who were at all able to appreciate its 

 importance and value. 



M. Oersted's own account of this discovery has been published 



o 2 



