d8 Proceedings of Philosophical Societies. [JaN4 



the direction of the ntjedle was soon changed, it bepjan to turn 

 round, and the velocity of its revolutions increased, till they 

 became too rapid to be counted. 



" M. Arago made the same trials with other metallic sub- 

 stances, and with similar results, differing, as might be expected, 

 in intensity ;" and these experiments have been repeated, con- 

 firmed, and extended, by MM. Herschel, Babbage, and. 

 Christie. 



" It is for the discovery of this fact, the power of various 

 bodies, principally metallic, to receive magnetic impressions in 

 the same, though in a more evanescent manner than malleable 

 iron, and in an infinitely less intense degree, that your Council 

 have awarded your medal to M. Arago; and you, I am sure, 

 cannot but approve of their decision ; for whether in its imme- 

 diate relations, or ultimate applications, there is no physical 

 fact which has been made known during the present year, that 

 can with propriety be put in competition with it. 



" By extending the empire of magnetism to a number of 

 bodies, it removes much of what was mysterious and inexplica- 

 ble in that department of science, and renders it a branch of the 

 general philosophy of nature ; and when the new analogies 

 between magnetic and electrical action established by these 

 phaenomena are considered, there is much reason to hope that 

 they may be ultimately referred to the same cause, and, with 

 chemical affinity, possibly be found identical with the general 

 quality or powei of attraction of gravitation." 



Sir Humphry Davy then adverted to the scientific labours of 

 Mr. Barlow, and passed a well-merited encomium on his papers 

 published in the Transactions of the Royal Society, which, he 

 observed, establish his character as a judicious and accurate 

 experimenter, and an able reasoner ; but though the facts and 

 reasoning brought forward in those memoirs would undoubtedly 

 have claimed the attention of the Council, and migiit have led 

 them to balance Mr. Barlow's merits Vi^ith those of other contri* 

 butors to the Philosophical Transactions, " their opinion was 

 fixed, and their decision formed, by a practical application of 

 science of great ingenuity and of considerable utility." 



IMasses of iron become magnetic by the action of the earth : a 

 bar of soft iron, for instance, held vertically, has its north pole 

 uppermost, and attracts the needle in the same manner as the 

 pole of the eirth; and all masses of iron, following the same 

 law, exert an action on the needle proportional to the square of 

 the distance, and of course destroy, or diminish in a certain 

 ratio, the action of the north pole of the earth. " It is extraor- 

 dinary that so important a circumstance as the action of the 

 iron in a ship on the needle had not earlier and more strongly 

 arrested the attention of navigators. Even Dr. Halley, the most 

 accomplished and profound philosopher that ever made long 



