316 PROCEEDINGS OF SECTION B. 



distance from the iron are converted into hydrated ferric 

 oxide, and afterwards carbonate and silicate of ferrous 

 oxide, the latter being produced by the oxidation of silicate 

 of iron, 



p. 186 : 6. " At ordinary temperatures, and out of contact 

 of air, iron does not decompose thoroughly boiled water, 

 unless it is in contact with more electro- negative bodies, as 

 with previously formed ferric oxide, mercury, &c. In this 

 case, and likewise when the liquid is heated to 50° or 60°, a 

 feeble evolution of hydrogen takes place, and ferroso-ferric 

 oxide appears to be formed. — (Hall, 2 J.C.S., vol. 7, p. 55. 

 Guibouit, Ann. Chem. Phys., vol. 11, p. 43.) 



p. 187: "Ferrous oxide decomposes water by continued 

 contact, and is converted into ferroso-ferric oxide. 



]). 188: "If a ferrous salt be precipitated by ammonia 

 instead of by potash, the precipitate, after long standing, 

 gives off hydrogen gas, becomes gradually darker in colour, 

 and when dried in the manner above described is converted 

 into black ferroso-ferric oxide containing ammonia. — (G. 

 Schmidt, Ann. Pharm., 36, 101.) 



" Dried ferrous hydrate is not magnetic (Liebig and 

 Wohler), and on exposure to the air it is instantly converted 

 into ferric oxide. The heat often rises to redness. 



p. 193: "Iron black or iEthiops ( Martialis Lemeryi) 

 is a mixture of ferric and ferrous oxides in different pro- 

 portions, according to the mode of preparation, and is partly 

 hydrated. 



p. 194 : " Hydrated iEthiops. — Iron fihngs are placed in a 

 wide vessel covered with a deep stratum of water, exposed to 

 the air for a considerable time with frequent stirring, the light 

 black powder is decanted from the still unoxidised iron from 

 time to time, collected on a filter, and rapidly dried. This 

 preparation is doubtless identical with the black hydrate of 

 ferroso-ferric oxide already described." 



The above quotations are given because they give a more 

 accurate account of the process of the oxidation of iron 

 than some of the more modern writers. 



J. Robbins, in a Note on " Magnetic Peroxide of Iron " 

 Chemical Aeios, voi. i., 1859, p. 11, states that he ignited 

 some black magnetic oxide of iron on platinum foil over a 

 spirit lamp. " After ignition the black oxide had apparently 

 become converted into the common red peroxide of iron, but 

 on applying the magnet, to my great astonishment I found 



