2. The Italian method, a variation of the Catalan, which requires more skill on the part of the workmen and yields more iron than the preceding.
As these methods seem to me of interest, from the standpoint of their simplicity and easy installation, I propose to describe them briefly, in order to give as faithful and general an aperçu as possible of their application. At present I shall deal with the first one only, the one called the method by Cadinhes.
STUDY OF THE METHOD BY CADINHES.
The province of Minas Geraes ocupies a vast extent in the empire of Brazil, its superficies being about 900,000 square kilometers, representing nearly a third of the total surface.
The population is relatively small and is disseminated throughout a much broken country, where the means of communication are very few. So it is necessary to succeed in producing what iron is needed by means that are simple and that require but quickly erected works built of such material as may be at hand. The iron ore is found in very great abundance in this region and is very easily mined.
In the center of a mass of quartzites that seem lo constitute the upper level of the eruptive grounds of the province, there are found strata of an ore of iron designated as itabirite--a mixture of oxide of iron and quartz. These strata are of great thickness, and have numerous outcrops that permit of their being worked by quarrying.
These itabirites present themselves under two very distinct aspects and offer a certain difference in their composition. Some are essentially friable, and are called by the vulgar name of jacutingaes. It is this variety (which is the one most easily mined) that is principally consumed in the forges. The others, on the contrary, are compact. Their exploitation is more difficult, and before putting them into the furnaces it is necessary to submit them to breakage and screening; so the use of them is more limited.
The first variety contains less iron and more gangue, but, per contra, possesses much oxide of manganese. The second, on the contrary, is formed almost wholly of oxide of iron with but little gangue and only traces of oxide of manganese. The following are analyses of these two varieties of ore:
| Friable Ore | |
|---|---|
| Fe2O2 | 84.9 |
| Oxide of manganese | 9.2 |
| Water | 1.9 |
| Quartz | 4.1 |
| ------ | |
| 100.1 | |
| Compact Ore | |
|---|---|
| Fe2O3 and traces ofmanganese | 99.6 |
| Quartz | 1.1 |
| ------ | |
| 100.7 | |