_Furnace_.--The work lasts about twelve hours per day, and three operations of three to four hours are performed in each cadinhe, thus making twelve per day. At each operation, 22.5 kilos. of ore and 45 of charcoal are used. From this there is obtained a bloom of 15 kilos. The operation is performed as follows:
While the assistant has gone to put the bloom of the preceding operation under the hammer, the workman prepares at the bottom of the crucible a bed consisting of a mixture of sand and very fine charcoal, and then fills the crucible up to its edge with charcoal. At the end of a quarter of an hour, the fuel being thoroughly aglow, the workman puts in the first charge of ore in powder (_jacutingue_), about 2 kilos, and covers it with charcoal.
Starting from this moment, he goes on charging every five or ten minutes with 1.5 to 2 kilos of ore, taking care in doing so to keep the crucible stuffed with charcoal, which the assistant places in piles around each cadinhe. This lasts about two and one-half hours. At the end of this time he stops putting in charcoal, and standing upon the masonry, walks from one cadinhe to another, carrying a large rod, in order to study the lay of the bloom. Then, the fire being entirely out, he scrapes out the bed of sand and charcoal that closes the opening in the bottom of the crucible, removes the mass of ferruginous scoriæ which forms a hard paste and surrounds the bloom, and takes this latter out by means of a hook.
The workman runs the four cadinhes at once, this being easily enough done, since he has neither to bother himself with regulating the wind, which enters always with the same pressure, nor with the flow of the scoriæ, which remain always at the bottom of the crucible. His role consists simply in keeping his fires running properly, being guided in this by the color of the flame without making an examination in the interior. He draws each of the four blooms out from its bed at the end of the operation, while the assistant carries the first to the hammer and the three others to the reheating furnace. He afterward cleans out the crucible, prepares the bed of sand and charcoal, fills with charcoal, and then passes to the next, and so on.