204 



MAGNETISM 



1.1. 



the substance resembled iron, the bar set itself "uxially, 

 with its longer axis along the line NS, Fig. 157, joining the two 

 poles, and he classed all such substances together as paramagnetic*: 

 If it resembled bismuth or antimony the bar set itself "equa- 



r 



FIG. 107. 



torially," i.e. along the line crat right angles to N S, and all >uch 

 substances he designated diamagneiict. 



Liquids. By enclosing liquids in gla>^ vessels Farada\ \\a^ 

 enabled to determine to which cla>s thcv belonged. Thus hi- found 

 that solutions of salts of iron are paramagnetic, while alcohol and 

 water are diamagnetic. 



Gases. He also succeeded in showing the magnetic character 

 of gases in several ways. For instance, if a stream of gas rendeird 

 evident by traces of ammonia and hydrochloric acid was allowed 

 to ascend between the poles, if dinmagnetk it divided into h\< 

 streams pushed out from the central region. Bubbles filled \\ith 

 the various gases were attracted into or repelled from the central 

 space between the poles. He found from hi> cxpcrimi-nt> that 

 oxygen in air is strongly magnetic, while nitrogen and hulrogrn 

 are diamagnetic. The following Table gives a feu of tin- mon 

 important substances, arranged under the two heads, air being the 

 medium surrounding the poles (A'./y;. Res. vol. iii. p. 71): 



PARAMAGNETIC 



Iron 

 Nickel 

 Cobalt 

 Mangam-M- 

 Crown G lav- 

 Platinum 



DIAMAGNETIC 



Araenic 

 Ether 



Alcohol 



Gold 



Water 



.Mercury 

 Flint (ila>- 



I It -a\ v (ila 

 Antimonv 



Bismuth 



