IRON MANUFACTURE. 513 
These very highly phosphorated irons are interesting rather from a 
metallurgical than a commercial point of view; still they find a market, 
being used to some extent as softeners in foundry mixtures. The 
introduction of the basic steel process would open a wide field of use-_ 
fulness for these irons. It is possible that trial has been made of them 
for this purpose, as Mt. Vernon furnace has lately found a special mar- 
ket for quite a quantity of this metal. 
Taking the average of the above analyses, the formula of the slag 
shows it to be a bisilicate or one containing half enough base (lime and 
alumina) to saturate the silicic acid. The character of the slag corre- 
sponds to this formula; it is glassy and thick, and solidifies slowly. 
The iron is unusually high in silicon for a charcoal iron, probably 
because the slag is so high in alumina, compared to the lime and silica, 
as to give it a refractory character and necessitate too high a tempera- 
ture in the furnace. ‘The effect of much silicon appears to be to injure 
or destroy the chilling property of the iron. 
| The only methods of utilizing the gases of the charcoal furnaces 
are those described and figured in connection with Howard furnace, 
Figure II. This method is perhaps as well adapted as any to the 
small amount of gas produced in these furnaces, though the large 
amount of fuel used will result in the production of more gas than 
is usual in charcoal smelting. To make an estimate of the actual 
amount of gas produced, it is necessary to know the composition of the 
charge, the fuel and the iron produced. Calculations, based on the 
charges already given, and restated here for reference, may be made, 
and will give approximate results. Hxact results as to amount of gas 
and blast could only be obtained on knowing the composition of the 
furnace gases. In detault of this a fair average composition will be 
assumed, making due allowance for the large amounts of fuel used in 
these furnaces, the effect of which will be to largely increase the ratio 
between the carbonic acid and carbonic oxide in the gas. 
The charges referred to represent the working of one of the best 
charcoal furnaces of the Hanging Rock region. The analyses were 
taken from the furnace records in most cases, and represent well averaged 
samples : 
33 G. 
