WATER-PRESSURE ENGINE-SECTIONAL ELEVATION, Folding Plate at end

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ERRATA.

Page 69-Hyperbolic Logarithms, first column, line 6, for 12 read 1.3.

183-Line 12 from bottom, for cuperous, read cupreous.

MINING AND METALLURGY:

HISTORICAL NOTICE.

In the time of Moses, at least six metals were known, since, in his direction for the purification of the spoils of the Midianites, he says: Only the gold and the silver, the brass, the iron, the tin, and the lead, every thing that may abide the fire, ye shall make it pass through the fire and it shall be clean.* Thus showing that the metallurgic arts had at that early period attained considerable perfection, and that the metals were of frequent occurrence and constant employment. Of the various metallurgic processes practised in the early ages of the world, little can be at present known; but it would appear likely, from some passages in the sacred writings, as well as from the somewhat confused and obscure accounts of profane authors, that they differed but little from those which are employed at the present day.

That silver was at a very early period purified by means of lead, the following passages would seem to indicate: "The house of Israel is to me become dross; all they are brass, and tin, and iron, and lead in the midst of the furnace, they are even the dross of silver." And again, "The bellows are burned, the lead is consumed of the fire, the founder melteth in vain." We also read of silver being purified in a furnace of earth. Strabo quotes Polybius as speaking of a silver ore which, after being washed seven times, was melted with lead and became pure silver.

That tin was not only well known, but also highly valued, at the time of the Trojan War, we learn from Homer, who calls it KaoσiTɛpos, and mentions it as forming part of the armour of Agamemnon,§ and shield of Achilles, to make which, Vulcan is

Numbers xxxi. 22. § Iliad, 2.

Ezek. xxii. 18. || Iliad, 18.

Jer. vi. 29.

B