354

BOOK IX.

smelters by which of these methods they can obtain the most metal fromany one ore. Moreover, while sometimes there are many methods ofsmelting the same ore, by which an equal weight of metal is melted out, yetone is done at a greater cost and labour than the others. Ore is either meltedwith a furnace or without one ; if smelted with a furnace the tap-hole is eithertemporarily closed or always open, and if smelted without a furnace, it is doneeither in pots or in trenches. But in order to make this matter clearer, I willdescribe each in detail, beginning with the buildings and the furnaces.

It may be of service to give a tabular summary indicating approximately the timewhen evidence of particular operations appear on the historical horizon :

Gold washed from alluvialCopper reduced from ores by smelting ..

Bitumen mined and usedTin reduced from ores by smeltingBronze made

Iron reduced from ores by smeltingSoda mined and usedGold reduced from ores by concentrationSilver reduced from ores by smeltingLead reduced from ores by smelting

Silver parted from lead by cupellation ..

Bellows used in furnaces ..

Steel producedBase metals separated from ores by water concentratioiGold refined by cupellationSulphide ores smelted for lead ..

Mercury reduced from ores by..(?)

White-lead made with vinegar ..

Touchstone known for determining gold and silverfineness

Quicksilver reduced from ore by distillationSilver parted from gold by cementation with saltBrass made by cementation of copper and calamineZinc oxides obtained from furnace fumes by construc-tion of dust chambersAntimony reduced from ores by smelting (accidental)Gold recovered by amalgamationRefining of copper by repeated fusion .

Sulphide ores smelted for copperVitriol (blue and green) made ..

Alum made

Copper refined by oxidation and polingGold parted from copper by cupelling with leadGold parted from silver by fusion with sulphurManufacture of nitric acid and aqua regiaGold parted from silver by nitric acid ..

Gold parted from silver with antimony sulphideGold parted from copper with sulphurSilver parted from iron with antimony sulphideFirst text book on assayingSilver recovered from ores by amalgamation ..Separation of silver from copper by liquation..

Cobalt and manganese used for pigmentsRoasting copper ores prior to smeltingStamp-mill used ..

Bismuth reduced from ore

Prior to recorded civilizationPrior to recorded civilizationPrior to recorded civilizationPrior to 3500 B.C.

Prior to 3500 B.C.

Prior to 3500 B.C.

Prior to 3500 B.C.

Prior to 2500 B.C.

Prior to 2000 B.C.

Prior to 2000 B.C. (perhaps priorto 3500 B.C.)

Prior to 2000 B.C.

Prior to 1500 B.C.

Prior to 1000 B.C.

Prior to 500 B.C.

Prior to 500 B.C.

Prior to 500 B.C.

Prior to 400 B.C.

Prior to 300 B.C.

Prior to 300 B.C.

Prior to Christian EraPrior toPrior to

Prior toPrior toPrior toPrior toPrior toPrior toPrior to

Prior to 1200 A.D.

Prior to 1200 A.D.

Prior to 1200 A.D.

Prior to 1400 A.D.

Prior to 1400 A.D.

Prior to 1500 A.D.

Prior to 1500 A.D.

Prior to 1500 A.D.

Prior to 1500 A.D.

Prior to 1500 A.D.

Prior to 1540 A.D.

Prior to 1540 A.D.

Prior to 1550 A.D.

Prior to 1550 A.D.

Prior to 1550 A.D.

Prior to 1550 A.D.

Zinc reduced from ore (accidental) .. .. __ _

Further, we believe it desirable to sketch at the outset the development of metallurgicalappliances as a whole, leaving the details to special footnotes; otherwise a comprehensiveview of the development of such devices is difficult to grasp.

We can outline the character of metallurgical appliances at various periods infew words. It is possible to set up a description of the imaginary beginning of

a

the