IRON ITS COMPOUND TRACES. 87 



In like manner the 1st oxide of lead is yellow , the 2nd red. 

 According to Doctor Thompson the 1st, or protoxide of iron* 

 is blacky and is combined in the following proportions : 



100 Iron. 

 28 Oxygen. 



The 2nd, or peroxide* is dark red, and is a compound of 



Iron 100. 



Oxygen 42.295 



The traces by analogy that iron is a compound may be 

 considered probable from the following circumstances: 1st, 

 that it is known to combine with carbon, in many proportions, 

 ^- part of carbon forms soft cast steel ; 



4 ' ihi 



( Hfii 



part carbon common cast steel ; 



the same, but harder ; 

 ditto, too hard lor drawing ; 

 white cast iron ; 

 mottled cast iron ; 

 black cast iron ; 



plumbago. 



From Mr. Musket's Table. 



Doctor Thompson, in his analysis of iron, communicated by 

 him at the Liverpool Meeting of the British Association, 

 shows that iron contains 



Manganese 



Silex 



as well as Carbon, 



2ndly. That it combines with oxygen. 



3rdly. That it will not combine with hydrogen, nor nitrogen, 

 in their simple state; therefore, as constituents, they are in 

 excess. 



ithly. That iron affords brilliant light when ignited in 

 oxygen gas ; which it would not do, unless it possessed hydro- 

 gen and nitrogen. 



From the hypothetical theory here presented, we may reason, 

 speculatively, on the implied composition of several bodies, 



taking their actual color, or that of their combinations with 







