366 Mi". Mallet on the Physical Conditions 



fact. The fact itself has long been known in the iron works of northern Europe, that 

 pyrites, in the blast furnace, will produce white iron, or an approach to it; and, pos- 

 sibly, it has been occasionally resorted to with the intention of producing this end. The 

 rationale of the process, however, is not that suggested by the reporters, but has been 

 fully developed by Janoyer, "Ann. des Mines.," 4 ser. t. xx. p. 359, and elsewhere, who 

 has shown that sulphur and carbon mutually eliminate each other, by combining in the 

 blast furnace, and becoming volatilized, as sulphuret of carbon. But, although this be 

 chemically true, and a fortunate condition in always aiding in the expulsion of sulphur 

 from crude iron, no prudent iron-master would dream of voluntarily resorting to such a 

 method of obtaining mottled iron as this, in#much as no care or skill in the working of 

 the blast furnace could insure, for an hour together, the production of pig-iron, that should 

 not contain an excess of sulphur. The method, too (as is obvious from the text) is as 

 needless as it would be perilous to the quality of the product. 



Sulphur, in the state of sulphates, or other saline combinations, cannot but be intro- 

 duced into the blast furnace, whether we use our own raw coal, washed coal as in Belgium, 

 by which a material reduction of impurity is obtained, coke, anthracite, or even wood, 

 in whose ashes sulphur is not absent, any more than in the majority of the limestones used 

 as flux. Berthier and others have clearly shown, that the amount of sulphur finally 

 included in the yield of iron, is not in proportion to the sulphur contained in the fuel or 

 flux, but depends upon a multitude of conditions in the working of the furnace, and chiefly 

 upon the proportion of lime in the flux, and on the temperature of the furnace ; but, that 

 a sensible improvement in the quality of the pig-iron has been obtained in Belgium, by 

 washing the coal, so as to oxidize the contained pyrites into copperas (sulphates), and thus 

 remove it in solution, appears certain ; and the marked differences noticed between irons, 

 made with coal which contained sulphur in the proportions of 0'28 per cent, and of 0-64 

 per cent., in favour of the former (Janoyer), indicate that the washing process, extended to 

 coke, and given sufiicient time, would, in Great Britain, be attended with the best effects 

 as respects the production of iron for gun-founding. Coal fuel is much deteriorated in 

 heating and " bearing" power by washing; but not so coke, which may be exposed to air 

 and water (if frost do not supervene), for a length of time, without injury to it as fuel. 



A most important contribution to our knowledge of all that relates to the iron industry 

 of Belgium and France, worthy of being better known in English, has been made by the 

 '• Reports upon the Condition and State of the Iron Manufactures of Belgium and of France," 

 by M. Hector Rigaud, Eng. Civ. des Mines. (Ann. des Mines, 4 ser. t. viii. p. 371, &c.) 



It is by no means certain, however, to what e.xtent, or if at all, the presence of minute 

 proportions of sulphur reduces either the tenacity, or the toughness, of cast-iron of given 

 quality in other respects ; certain it is, that these depend more, nay, primarily, upon the 

 proportion and molecular condition of the carbon it contains, and that the alloy of small 



