1868. | Metallurgy and Mining. 253 
out the addition of any other fuel. We were informed that some 
experiments were about to be made with those dead oils in the 
locomotives for the coal trains of the Caledonian Railway. 
It is well known that lead, with a specific gravity of 11-5, will 
float on molten iron, the specific gravity of which is 7... There has 
ever been some difficulty in explaining this phenomenon. Pro- 
fessor Karmarsch, of Hanover, has lately, with the assistance of an 
ironmaster, been examining the subject. It appears that the 
moment the lead melts it forms a spheroid, which is hollow, and 
hence specifically lighter than the iron. The Professor supposes 
the formation of some vapour of lead, which becomes enclosed in 
the shell formed. Is it not probable that this is only another 
condition of the well-known spheroidal state of matter? Certain 
ores of iron contain sometimes considerable quantities of lead. 
When these are smelted, it is not unusual to find the lead “sweated 
out” at the bottom of the pig of iron, where we should expect to 
find it, according to its specific gravity. 
A paper was read before the Liverpool Polytechnic Society, at 
the end of the year, “On the Manufacture of Steel from Cast-iron ” 
by the use of nitrates and other oxidizing salts, by Mr. J. Har- 
greaves. The object of the invention is to effect the acieration of 
cast-iron by a direct process, and thus dispense with the many 
permutations which it is at present made to undergo before the 
condition of steel is attamed. ‘This is effected by the agency of 
oxidizing salts and oxides cf iron and manganese. The oxidizing 
salts which are most suitable for the purpose are the nitrates, and 
especially the nitrate of soda, on account of its low cost, higher per- 
centage of oxygen, and the highly electro-positive character of its 
base, which renders it a most effective agent in removing the 
metalloids—silicium, sulphur, and phosphorus—and the semi-metal 
arsenic from iron, by forming with them compounds of sodium, 
thus enabling inferior qualities of cast-iron to be used in the manu- 
facture of steel, and also to improve the qualities of malleable iron 
by depriving it of those objectionable substances. 
The above seems to be but a modification of Headon’s process, 
which process was mentioned in a former number of the Journal. 
There have been several patents taken out of late for improve- 
ments in the casting of Bessemer steel. Mr. James Astbury, of 
Smethwick Foundry, has patented a scheme for preventing the 
irregular cooling and chilling of the metal when poured into the 
iron moulds from the Bessemer ladle, which often produce cavities, 
of a honeycombed appearance, in the middle of the casting. For 
this purpose the moulds are made of plumbago, and previous to 
casting they are heated in a furnace sufficiently to prevent the 
metal from solidifying, and then when full are gradually cooled 
from the lower part, and as contraction takes place, the fluid metal 
2 
