288 THE SCIENTIFIC PAPERS OF 



takes place in a blast furnace. As the percentage of manganese 

 in the pig increases, so does the sulphur decrease ; for instance, if 

 to ore and coke, which in the ordinary way will produce a pig 

 containing from 2 per cent, to 3 per cent, of sulphur, mangani- 

 ferous ore is added so as to put 2 per cent, of manganese into the 

 pig, the sulphur will be reduced to "05 or '08 per cent. ; but when 

 3 per cent, of manganese is found in the pig it never contains 

 more than a slight trace of sulphur. "We have had occasion lately 

 to analyse several hundreds of samples of pig iron made under 

 these conditions, and can vouch for the accuracy of this state- 

 ment, and we think it a fact well worth the attention of iron- 

 masters who are troubled with an excess of sulphur either in their 

 ores or fuel. 



" Every one must have noticed the absence of sulphur in all 

 analyses of spiegeleisen, although much of it is made from coke, 

 and most of the ores used contain a considerable quantity of pyrites. 



" That the manganese acts by its actual presence, and not by any 

 chemical reaction, is. we think, proved by the fact that, if through 

 any accident or carelessness of the workmen, the charge is left in 

 the furnace for more than twenty minutes after the spiegeleisen is 

 fairly melted the steel is invariably bad, owing to the oxidation of 

 the manganese, and therefore if such delay occurs, a small addition 

 of spiegeleisen is made, and no bad results follow." 



About the impurities of steel the same gentlemen report : 



" The presence of sulphur, it is well known, makes steel red- 

 short, and the only question is, how much may it contain without 

 injury ? Our experience is, that up to 0'08 per cent, will do no 

 harm, provided there is also present 0'3 per cent, of manganese, 

 and we have even found '112 per cent, without having any com- 

 plaint from the hammermen. 



"Phosphorus does not appear to affect either the rolling or 

 hammering of steel, even if 0'2 per cent, is present, but if it ex- 

 ceeds 0*08 per cent., the rails become so cold-short that they will 

 not stand the severe test to which they are subjected. 



" The presence of arsenic and phosphorus increases the hardness 

 of steel at the expense of its toughness. 



" The effect of copper is not yet understood ; according to 

 Percy it renders steel red-short to a greater extent even than the 

 same amount of sulphur. 



