OF SOUTH CAROLINA. 273 
tions formed, but these are the principal. The proportion of the materials is, of course, important, 
and should be noted with care. 
There is a certain point of richness at which ores work more freely, and to bring the poor sorts 
up to this point, a mixture with richer ores becomes necessary. But, in all cases, the nature of the 
ores must be kept in view. It is the practice of some of the furnaces to mix the brown, red, and 
magnetic ores, for the purpose of giving the iron the desired qualities. For instance, the magnetic 
ores produce a soft, but exceedingly tenacious iron, well adapted for bolts, chains, cables, &c. but 
not well fitted for horse-shoes or wheel-tires. 'The brown ore produces a harder iron; and, by mix- 
ing both, one of medium quality is produced. Now it appears to me that this is a very doubtful 
practice; and, at all events, this tempering could be quite as well done in the subsequent process to 
which the pigs are subjected, when the two could be combined. 
It will be recollected that the brown and red ores are peroxides, having two equivalents of iron, 
combined with three of oxygen, and that the magnetic ore is composed of two equivalents of per- 
oxide, combined with one of the protoxide—consequently the magnetic ages have less oxygen to part 
with than the others, and would be reduced before them. Theoretically, then, the practice of mix- 
ing the three ores must be wrong. 
The difference between the red and magnetic ores is not so great, as I have shown that they 
contain a portion of the protoxide, and the deeper in the vein the more is present. 
Unless there be some better reason for this admixture than the mere tempering of the iron, this 
practice should be examined more closely. 
The brown ore alone produces good iron, adapted to all ordinary purposes, and it is easy, as I 
have said, to combine the pigs with those of the magnetic ores, in the finery or elsewhere. 
The compact magnectic ores, although much richer, are less valued, because they are much 
more unmanageable than the other varieties; and this difficulty is not peculiar to South Carolina 
ores, but is felt elsewhere. 
We owe to Prof. Emmons* the knowledge of some highly interesting investigations, made by 
Mr. Henderson, at the Adriondae Iron Works, Clinton County, New York, and undertaken with the 
view of elucidating some of the difficulties attending the reduction of magnetic ores. 
It has been already stated that these ores are composed of one atom of protoxide, and two of 
peroxide ; but it appears, from these experiments, that the two do not exist in any thing like an 
intimate combination, but, taken in mass, the ores consist of an irregular mixture of the two. 
Before proceeding to the experiments, it will be necessary to mention briefly a process, discovered 
by Mr. Clay, for reducing rich ores, by means of a far less amount of charcoal than the old method. 
The ore is first pulverised, then mixed with fine charcoal, and placed in a fire-proof retort or cruci- 
ble—the air being carefully excluded during the process. The vessel containing the ore is raised 
to, and retained at, a cherry-red heat, for six or eight hours—the combustion being kept up by the 
oxygen of the ore, which combines with carbon, and forms carbonic acid—leaving the iron deprived 
of its oxygen, or reduced. The particles of the reduced ore are next welded, by being raised to a 
white heat, in the forge, and then placed under the hammer. And, what is highly interesting in an 
*New York Reports. 
63 
