BOOK IX,

376

described above, is drawn backward and forward upon narrow boards ofequal length placed over a long box ; the powder which falls through thesieve into the box is suitable for the mixture ; the lumps that remain in thesieve are thrown away by some people, but by others they are placed underthe stamps. This powdered earth is mixed with powdered charcoal, moist-ened, and thrown into a pit, and in order that it may remain good for a longtime, the pit is covered up with boards so that the mixture may notbecome contaminated.

They take two parts of pulverised charcoal and one part of powderedearth, and mix them well together with a rake ; the mixture is moistened bypouring water over it so that it may easily be made into shapes resemblingsnowballs ; if the powder be light it is moistened with more water, if heavywith less. The interior of the new furnace is lined with lute, so that thecracks in the walls, if there are any, may be filled up, but especially in orderto preserve the rock from injury by fire. In old furnaces in which ore hasbeen melted, as soon as the rocks have cooled the assistant chips away, witha spatula, the accretions which adhere to the walls, and then breaks themup with an iron hoe or a rake with five teeth. The cracks of the furnace arefirst filled in with fragments of rock or brick, which he does by passing hishand into the furnace through its mouth, or else, having placed a ladder againstit, he mounts by the rungs to the upper open part of the furnace. To theupper part of the ladder a board is fastened that he may lean and reclineagainst it. Then standing on the same ladder, with a wooden spatula, hesmears the furnace walls over with lute ; this spatula is four feet long, a digitthick, and for a foot upward from the bottom it is a palm wide, or evenwider, generally two and a half digits. He spreads the lute equally over theinner walls of the furnace. The mouth of the copper pipe 9 should not pro-trude from the lute, lest sows 10 form round about it and thus impede themelting, for the furnace bellows could not force a blast through them. Thenthe same assistant throws a little powdered charcoal into the pit of the fore-hearth and sprinkles it with pulverised earth. Afterward, with a buckethe pours water into it and sweeps this all over the forehearth pit, and with thebroom drives the turbid water into the furnace hearth and likewise sweepsit out. Next he throws the mixed and moistened powder into the furnace,and then a second time mounting the steps of the ladder, he introduces therammer into the furnace and pounds the powder so that the hearth is madesolid. The rammer is rounded and three palms long ; at the bottom it is fivedigits in diameter, at the top three and a half, therefore it is made in the formof a truncated cone ; the handle of the rammer is round and five feet long and

9 It has not been considered necessary to introduce the modern term twyer in these des-criptions, as the literal rendering is sufficiently clear.

10 Ferruminata. These accretions are practically always near the hearth, and wouldcorrespond to English “ sows,” and therefore that term has been adopted. It will be notedthat, like most modern metallurgists, Agricola offers no method for treating them. Pliny(xxxiv, 37) describes a “ sow,” and uses the verb ferruminare (to weld or solder) : “ Some“ say that in the furnace there are certain masses of stone which become soldered together,

" and that the copper fuses around it, the mass not becoming liquid unless it is transferred“ to another furnace ; it thus forms a sort of knot, as it were, of the metal.”