298 GEOLOGY OF THE SECOND DISTRICT. 



and the tools made from them bore harsh usage. Now it is to be borne in mind, that the 

 greater proportion of this kind of ore is in a state of protoxide, which being reduced first, 

 finds means to combine with the vapor of carbon and form steel ; and it is not impossible that 

 this state of oxidation may be better suited to the manufacture of steel, than the higher states 

 of oxidation. 



The importance of the preceding facts can not be well estimated, except by those who have 

 experienced the difficulties of working the mixed oxides. Some have been toiling and search- 

 ing for some poisonous substance in the ore ; some have been examining the kinds of earth 

 mixed in them ; while others have been trying various fluxes, to secure a uniform fusion, or 

 to form a slag which should cover the reduced ore and prevent its combining with carbon. 

 V'arious expedients have been resorted to, all having the same end in view ; but no one 

 thought that the different degrees of oxidation might be at the foundation of all the difficul- 

 ties. Such, however, is the most rational theory ; a theory which, it seems now, might be 

 supported by an a priori argument, but at any rate is sustained by experiment. The credit 

 of this discovery is due to Mr. Henderson, who, with great perseverance in experiments con- 

 ducted for two months in trying Mr. Clay's method, has conclusively shown not only what 

 were the causes of all former difficulties in working these ores, but what will be essential to 

 complete success in working them hereafter. 



After the preceding remarks and facts, it will appear to reflecting minds that all that is 

 essential and requisite to make good iron of these mixed ores, by any of the methods now in 

 use, is to separate the two oxides by the magnetic machine. This is all that is essential. It 

 will undoubtedly be useful to roast the ores in the first instance ; for by this process, some 

 portions lose sufficient quantity of oxygen to become magnetic ; the magnetism of the whole 

 seems also to be stronger after roasting, than before. This operation not only separates the 

 two oxides, but separates also the pure ore from rock and earth. The latter in certain pro- 

 portions is not specially injurious in the forge ; but when Mr. Clay's method is contemplated, 

 the purer the ore is, the greater is the certainty in the last process. When the ore is a peroxide 

 mixed with stone and earth, and needs separating, the washing process will probably be the 

 most suitable, or the cheapest. I find it is preferred by several gentlemen in the iron busi- 

 ness, who have tried both methods. The magnetic machine is capable of separating six tons 

 of ore per day, a quantity which is sufficient to supply a forge for one week. 



Rodi investing the veins of the Arnold hill, and its simple ininerals. 



The rocks immediately investing or embracing the veins described in the preceding para- 

 graphs, is a deep red granite, though the rock of the surrounding country is generally gneiss. 

 The deep color of the granite appears to be partly owing to the great abundance of the peroxide 

 of iron in the immediate vicinity. Near its junction with the ore, it is traversed by thin veins 

 of feldspar, of iron, granite of a diff'erent kind from that of the main rock, jaspery iron, etc. 



The simple minerals associated with the ore, or embraced in the rock, are by no means 



