296 GEOLOGY OF THE SECOND DISTRICT. 



In the first place, then, the protoxide and peroxide exist in different particles, or rather 

 crystals, in the same mass ; and their differences are often so well marked, that the peroxide 

 can be selected by the eye, the lustre and structure being sufficiently different to enable one 

 to see what parts are in a state of low oxidation, and those which are highly oxidated : the 

 latter are in laminated masses, with brilliant surfaces, while the former are of a dull black 

 color ; the former gives a brown streak, the latter black ; and if we resort to the magnet, 

 the bright laminated particles are uninfluenced, while the dull black ones immediately obey 

 and are taken up. It is therefore not as most chemists and mineralogists have conjectured, 

 an intimate mixture or blending of particles, but an irregular mixture of the two, in separate 

 and distinct crystals. 



Again, by observing the characters of the two oxides, we may satisfy ourselves that in 

 different veins the two oxides are entirely in different proportions ; and this fact led me to 

 remark, that one object in pursuing the chemical examination of the magnetic ores, was to 

 bring out and establish this same fact in every case, or to ascertain the proportions in which 

 the two oxides were combined in different veins ; for we now see that the proportions may 

 influence greatly the mode of working the ore, and may lead to new methods : those which 

 are composed largely of the protoxide may not only work very different from those which are 

 peroxidated, but, without being particular, a variety of important facts will grow out of this 

 alone. It is not a matter of so much importance to determine how rich an ore is, or how 

 much metal it contains, as in what proportions the two oxides are mixed, and which one 

 predominates over the other. I am satisfied that every vein will be constant in its proportions. 



Now the experiments of Mr. Henderson with the Adirondack ores, by Mr. Clay's plan, 

 resulted in a manner agreeable to the tenor of the above remarks. His manipulations con- 

 sisted in exposing the ores in a broken up state, without roasting, to pure charcoal in a siggar, 

 a kind of crucible, for thirty hours, at a red heat, and excluding atmospheric air. On 

 inspecting the pieces after filing and polishing, two different colors or appearances presented 

 themselves. What is described as the coarse black ore in this report, became mostly metallic 

 iron, as appeared by the filing, etc. ; but small black crystals were disseminated in the mass : 

 these were brittle, but obeyed the magnet ; while the former received the polish of iron, was 

 malleable, and hence was truly iron. In the annexed figure, Nos. 1 and 3 represent the 



Fig. 77. 



