66 



ANALYSIS OF MAGNETIC IRON-ORE. 



of oxygen, and of forming three oxides ; the 

 composition of each of which, is as follows : 



Iron. Oxygen. 



1. Protoxide, composed of, 100+15 



2. Beutoxide, - 100 + 15 X 2 = 30. 



3. Peroxide, - 100 + 1 5 X 3 zz 45. 



The second and third of these oxides are known. 

 They are the common black and red oxides of 

 iron. But we remain still unacquainted with the 

 first, which cannot be formed artificially by any 

 known process. 



It is by no means an unlikely circumstance, 

 that magnetic iron-ore consists chiefly of this 

 hitherto unknown protoxide. It differs in its pro- 

 perties from black oxide, being more soluble both 

 in sulphuric and muriatic acids, and effervescing 

 slightly during its solution, which is not the case 

 with black oxide. The circumstance also of its 

 being at least occasionally a permanent magnet, 

 ought not to be overlooked. Pure iron possesses 

 this property in a very trifling degree. Mr Hat- 

 chett has shewn, that iron may be converted into 

 a magnet, when combined with a minimum of 

 carbon, sulphur or phosphorus, but loses its mag- 

 netic virtue entirely when saturated with these 

 substances. It is not unlikely that the analogy 

 may be extended to oxygen likewise. Red oxide 

 of iron is not magnetic -at all : black oxide is im- 



