388 Miscellaneous Intelligence. 



yield a dull greyish black powder. They do not unite with acids 

 forming particular salts, but are resolved into protoxide and 

 peroxide, these forming salts with the acids. These scales were 

 not always of the same degree of oxidation, but when most 

 constant, gave 



Iron . . . 745 . or . 100 

 Oxygen . . 255 . . . 34.2 



" I believe," says M. Berthier, " that this is the true composi- 

 tion of these scales, and that henceforth we must reckon upon four 

 oxides of iron in which the oxygen is as the numbers 6:7:8:9. 



The first is the protoxide — the second, the scales in question — 

 the third that obtained by passing steam over red-hot iron or the 

 natural magnetic oxide, and the fourth, the peroxide. — Jinn, de 

 Chim. xxvii. 19. 



1 0. Reduction of Oxide of Iron by Cementation. — M. Berthier lined 

 some crucibles with charcoal, and put into each about 1500 grains 

 of finely pulverised iron scales ; the crucibles were filled with 

 charcoal, well closed, luted, and heated for various periods of time, 

 from half an hour to three hours. When cold they were examined ; 

 the ferruginous substance had adhered together without any change 

 of form or volume ; the masses were enveloped in a layer of me- 

 tallic iron, and the oxide in the centre, more or less in quantity 

 according to the time the crucibles had been in the furnace, had 

 undergone no alteration. The metallic layer was in some cases 

 nearly 0.2 of an inch in thickness ; it had a very particular appear- 

 ance, was dull and granular in its fracture, and of a clear olive grey 

 colour. It acquired a bright polish from the friction of hard 

 bodies ; might be cut with scissors, and in this way reduced to 

 very fine powder ; it was as soft as lead, quite inelastic ; when 

 struck with a hammer, it flattened and took the form of the face of 

 the hammer. Its specific gravity was not more than one-third that 

 of pure forged iron. It was pure iron extremely divided, and in a 

 state analogous to that of spongy platinum. 



A section of a mass which had undergone long cementation, 

 presented the following order of things from the surface to the 

 centre; 1. Avery thin layer of metallic iron of a deep blue or 

 black colour; 2. A thick layer of the olive green iron of an uniform 

 colour; 3. A layer with shades of olive green and black, passing 

 into the pure black and slightly metallic appearance of the scales 

 themselves. The first appeared to be slightly carburetted, and to ap- 

 proach to the state of steel. The second was iron of the greatest 

 purity. The third, or olive green and black part, was a mixture of 

 iron and oxide, for it always gave red oxide by treatment in the 

 humid way; and this fact proves, says M, Berthier, that metallic 

 iron exerts no action on the oxide of scales, and consequently that 

 a protoxide cannot be obtained by the action of iron on any other 

 oxide of iron whatever. 



