494 BOOK XI. 



it is twenty feet long, and starts from the fourth long wall. The sixth 

 transverse wall is built also from the fourth long wall, at a point distant 

 thirty feet from the fourth transverse wall, and it extends as far as the back 

 of the third long wall. The seventh transverse wall is constructed from 

 the second long wall, where this first leaves off, to the third long wall ; and 

 from the back of the third long wall the eighth transverse wall is built, 

 extending to the end of the fourth long wall. Then the fifth long wall is built 

 from the seventh transverse wall, starting at a point nineteen feet from the 

 second long wall ; it is one hundred and nine feet in length ; and at a point 

 twenty-four feet along it, the ninth transverse wall is carried to the third end 

 of the second long wall, where that begins again. The tenth transverse wall is 

 built from the end of the fifth long wall, and leads to the further end of the 

 second long wall ; and from there the eleventh transverse waU leads to the 

 further end of the first long wall. Behind the fifth long wall, and five feet 

 toward the third long wall, the sixth long wall is built, leading from the 

 seventh transverse wall ; its length is thirty-five feet, and from its further 

 end the twelfth transverse wall is built to the third long wall, and from it the 

 thirteenth transverse wall is built to the fifth long wall. The fourteenth 

 transverse wall divides into equal parts the space which lies between the 

 seventh transverse wall and the twelfth. 



The length, height, breadth, and position of the walls are as above. 

 Their archways, doors, and openings are made at the same time that the walls 

 are built. The size of these and the way they are made will be much better 

 understood hereafter. I will now speak of the furnace hoods and of the roofs. 

 The first side^ of the hood stands on the second long waU, and is similar in 

 every respect to those whose structure I explained in Book IX, when I 

 described the works in whose furnaces are smelted the ores of gold, silver, 

 and copper. From this side of the hood a roof, which consists of burnt tiles, 

 extends to the first long wall ; and this part of the building contains the 

 bellows, the machinery for compressing them, and the instruments for 

 inflating them. In the middle space, which is situated between the second 

 and third transverse walls, an upright post eight feet high and two feet thick 



Historical Note. — So far as we are aware, this is the first complete discussion 

 of this process, although it is briefly mentioned by one writer before Agricola — that is, by 

 Biringuccio (in, 5, 8), who wrote ten years before this work was sent to the printer. His 

 account is very incomplete, for he describes only the bare liquation, and states that the copper 

 is re-melted with lead and re-liquated until the silver is sufficiently abstracted. He neither 

 mentions " drying " nor any of the bye-products. In his directions the silver-lead alloy was 

 cupelled and the copper ultimately refined, obviously by oxidation and poling, although he 

 omits the pole. In a.d. 1150 Theophilus (p. 305, Hendrie's Trans.) describes melting lead 

 out of copper ore, which would be a form of liquation so far as separation of these two metals 

 is concerned, but obviously not a process for separating silver from copper. This passage is 

 quoted in the note on copper smelting (Note on p. 405). A process of such well-developed and 

 complicated a character must have come from a period long before Agricola ; but further than 

 such a surmise, there appears little to be recorded. Liquation has been during the last fifty 

 years displaced by other methods, because it was not only tedious and expensive, but the 

 losses of metal were considerable. 



^Paries, — " Partition " or " wall." The author uses this term throughout in 

 distinction to murus, usually applying the latter to, the walls of the building and the former to 

 furnace walls, chimney walls, etc. In order to gain clarity, we have introduced the term 

 " hood " in distinction to " chimney," and so far as possible refer to the paries of these con- 

 structions and furnaces as " side of the furnace," " side of the hood," etc. 



