otton and silk stuff made in Turkey.
A process for the extraction of gold by exposure of the auriferous material to chlorine gas.
The process was first introduced by Plattner, a professor in the School of Mines, Freiberg, Saxony.
The principle involved is the transformation of metallic gold, by means of chlorine gas, into soluble chloride of gold (the aurum potabile of the ancients), which can be dissolved in cold water, and precipitated in the metallic state by sulphnot so many strings as keys, the strings being shortened, as in a guitar, by a device brought into action by the movement of the key, which struck the note.
We read in a Leipsic work of 1600 of an instrument brought by Praetorius from Italy to Saxony, in which each key had its own string.
This was considered quite a novelty in a keyed instrument, though common enough in harps, and was not fol- lowed till long afterwards, probably the latter half of the eighteenth century.
rified seven times. — Psalm XII. 6.
They gather silver, and brass, and iron, and lead, and tin, into the midst of the furnace to blow the fire upon it, to melt it, — Ezekiel XXII. 20.
From the former of these passages we may infer that a high degree of purity was attained by seven successive refinings.
Purifying the precious metals and then reducing their standard by means of alloying does not appear to have been generally practiced, and is not to this day in the East.
At Freiburg, Saxony, silver amalgamated by the barrel process is, after distillation, refined in crucibles, previously brought to a red heat.
The silver is gradually introduced in lumps, and when fused strewn with powdered charcoal, and the crucible covered with an iron plate.
After the lapse of a few minutes the impurities which had risen to the surface, together with the unconsumed charcoal, are skimmed off, more charcoal added, and the process repeated, occasionally stirring the molten metal, until its sur