162 On the geiieral Magnetic Relations of the Metals. 



ing small and powerful, so that the whole system was very 

 sensible to any substance capable of having magnetism in- 

 duced in it when brought near one of the four poles. Great 

 care was required and was taken to avoid the effect of the 

 downward current of air formed by the cooled body; very 

 thin plates of mica being interposed in the most important 

 cases. 



The following metals gave no indications of any magnetic 

 power when thus cooled to —112° Fahr. 



A piece of metallic manganese given to me by Mr. Everett 

 was very slightly magnetic and polar at covimon temperatures. 

 It was not more magnetic when cooled to the lowest degree. 

 Hence I believe the statement with regard to its acquiring 

 such powers under such circumstances to be inaccurate. Upon 

 very careful examination a trace of iron was found in the piece 

 of metal, and to that I think the magnetic property which it 

 possessed must be attributed. 



I was very careful in ascertaining that pure coSaZi! did not 

 become magnetic at the very low temperature produced. 



The native alloy of iridium and osmium, and also crystals 

 of titanium, were found to be slightly magnetic at common 

 temperatures ; I believe because of the presence of iron in 

 them.* Being cooled to the lowest degree they did not pre- 

 sent any additional magnetic force, and therefore it may be 

 concluded that iridium, osmium, and titanium may be added 

 as non-magnetic metals to the list already given. 



Carbon and the following metallic combinations were then 

 experimented upon in a similar manner, but all the results 

 were negative : not one of the bodies gave the least sign of 

 the acquirement of magnetic power by the cold applied. 



1. Carbon. 7. Native oxide of tin. 



2. Hasmatite. 8. manganese. 



3. Protoxide of lead. 9. Chloride of silver. 



4. antimony. 10. lead. 



5. bismuth. 11. Iodide of mercury. 



6. White arsenic. 12. Galena. 



[* See Dr. Wollaston's paper on this subject, Phil. Trans. 1823, Part II., 

 or Phil. Mag. First Series, vol. Ixiii. p. 15. Edit.] 



