Chemical Science. 387 



parts. More carbon will produce a mixture of two substances, 

 one steel, the other carburetted steel analogous to cast-iron ; these, 

 by slow cooling, will partially separate, and the mass of metal is 

 then capable of exhibiting a damask, the pure steel appearing of a 

 black colour, the extra carburetted parts white. 



As the separation of these substances must be proportionate to 

 the length of time which elapses before the fused metal solidifies, 

 M. Breant states, that it is sometimes proper to avoid the fusion of 

 masses so large as to be long in cooling ; and quotes a passage 

 from Tavernier, who, in his travels in Persia, says, that the fused 

 pieces of steel which come from Golconda, when worked, are not 

 larger than a roll. 



The more carbon the steel contains, the more difficult is it to 

 forge. jMost of those prepared by M. Breant could only be 

 worked at temperatures, of which the extremes were very limited ; 

 at a white heat they crumbled under the hammer, at a cherry-red 

 heat they became hard and brittle. The latter tendency, augmented 

 in proportion to the diminution of temperature, and to such an ex- 

 tent, that once below a red heat, they would, if tried with a graver or 

 file, be found much harder and more brittle than when quite 

 cold. 



M. Breant remarked, that 100 of soft iron and 2 of lamp-black 

 fused as readily as common steel ; and gave a compound, from 

 which excellent damasked blades were made. He considers it 

 unnecessary, therefore, to cement the iron with carbon as a preli- 

 minary step in the manufacture of steel. Another specimen of 

 Steel was made by fusing together 100 parts of very grey cast 

 iron in filings, and 100 parts of the same filings previously oxidated. 

 This steel was very elastic, and had a beautiful damask. The 

 result was such as to convince M. Breant, that steel might be 

 made on a large scale in reverberatory furnaces from the best grey 

 pig iron, by adding to the metal in fusion a portion of the same 

 metal oxidated, or native oxide of iron. 



Although M. Breant's results are by no means opposed to those 

 obtained by Messrs. Stodart and Faraday, yet he thinks it probable 

 they may have drawn erroneous conclusions, and attributed to the 

 presence of alloying metals, the effects really due to a greater pro- 

 portion of carbon. It may, perhaps, therefore, be as Avell to state, 

 that every source of carbon was carefully excluded in their experi- 

 ments. The tilted cast steel, and the alloying metal being care- 

 fully preserved from contact of any other substance than the 

 crucible and the plug of lute, which with the cover, ^c, were used 

 to confine it. — Annales des Mines, ix. 319. 



9. On the Scales of Iron. — M. Berthier has lately examined the 

 scales of oxide, which form on iron when heated; and after careful 

 analytical experiments, is induced to consider them as a new 

 oxide. They are biiitle, very uva|^uctic, sp. gr. 3.5 at least, and 



