BOOK VIII.

UESTIONS of assaying were explained in the lastBook, and I have now come to a greater task, thatis, to the description of how we extract the metals.First of all I will explain the method of preparingthe ore 1 ; for since Nature usually creates metalsin an impure state, mixed with earth, stones, andsolidified juices, it is necessary to separate most ofthese impurities from the ores as far as can be,before they are smelted, and therefore I will nowdescribe the methods by which the ores are sorted, broken with hammers,burnt, crushed with stamps, ground into powder, sifted, washed, roasted,and calcined 2 .

x As would be expected, practically all the technical terms used by Agricola in thischapter are adaptations. The Latin terms, canalis, area, lacus, vasa, cribrum, and fossa,have had to be pressed into service for many different devices, largely by extemporisedcombinations. Where the devices described have become obsolete, we have adopted thenomenclature of the old works on Cornish methods. The following examples may be ofinterest:—

Simple buddle = Canalis simplex Short strake = Area curia

Divided buddle = Canalis tabellis distinctus Canvas strake = Area linteis extensis contecta

Ordinary strake = Canalis devexus Limp = Radius.

The strake (or streke) when applied to alluvial tin, would have been termed a “ tye ”in some parts of Cornwall, and the “ short strake ” a “ gounce.” In the case of the stampmill, inasmuch as almost every mechanical part has its counterpart in a modern mill, wehave considered the reader will have less difficulty if the modern designations are usedinstead of the old Cornish. The following are the essential terms in modern, old Cornish,

and Latin :—

Stamp ..Stamper

Stamp-stem.. LifterShoes .. Stamp-heads.

Mortar-box . .BoxCam-shaft .. Barrell

.. Dentes.. Dili dentes

.. Laminae foraminum flenae. .Lacus

. . Pilum Cams .. Caps

..Pilum Tappets ..Tongues

.Capita Screens ..Crate

..Capsa Settling pit ..Catchers

.. Axis Jigging sieve . .Dilleugher . .Cribrum angustum2 Agricola uses four Latin verbs in connection with heat operations at temperaturesunder the melting point: Calefacio, uro, torreo, and cremo. The first he always uses in thesense of “to warm” or “to heat,” but the last three he uses indiscriminately in much thesame way as the English verbs burn, roast, and calcine are used ; but in general he uses theLatin verbs in the order given to indicate degrees of heat. We have used the Englisverbs in their technical sense as indicated by the context.

It is very difficult to say when roasting began as a distinct and separate metal-lurgical step in sulphide ore treatment. The Greeks and Romans worked both lead andcopper sulphides (see note on p. 391, and note on p. 403), but neither in the remains o olworks nor in their literature is there anything from which satisfactory details of such as epcan be obtained. The Ancients, of course, understood lime-burning, and calcined severalsalts to purify them or to render them more caustic. Practically the only specific mention isby Pliny regarding lead ores (see p. 391)- Even the statement of Theophilus (1050-1100, .d.),may refer simply to rendering ore more fragile, for he says (p. 305) m regard to copper ore :“ This stone dug up in abundance is placed upon a pile and burned (combuntur) after the“ manner of lime. Nor does it change colour, but loses its hardness and can be broken up," and afterward it is smelted.” The Probierbuchlein casually mentions roasting prior toassaying, and Biringuccio (111, 2) mentions incidentally that “ dry and ill-disposed ores“ before everything must be roasted in an open oven so that the air can get m. He givesno further information ; and therefore this account of Agricola’s becomes practically thefirst. Apparently roasting, as a preliminary to the treatment of copper sulphides, did not comeinto use in England until some time later than Agricola, for in Col. Grant Francis Smeltingof Copper in the Swansea District ” (London, 1881, p. 29), a report is set of the ‘ Doeinges ot" Jochim Ganse an imported German—at the “ Mynes by Keswicke in Cumberland,“ a.d., 1581,” wherein the delinquencies of the then current practice are described : inei

“ never coulde, nether yet can make (copper) under xxii. tymes passinge thro the fire, andxxii. weekes doeing thereof ane sometyme more. But now the nature of these ix. hur u“ humors abovesaid being discovered and opened by Jochim’s way of doeing, we can, by ms“ order of workeinge, so correct theim, that parte of theim beinge by nature hurtfull to me