Secondly, the ancients obtained, as we do, a great deal of lead from argentiferous ores, from which they separated the silver and revived the lead. The ore was pounded very fine, or, as we say, stamped; it was then washed and roasted, and formed into a powder or paste. This was then put into the furnace, and by the first fusion gave a regulus consisting of silver and lead, which was called _stannum_, and was the same substance as that known to our metallurgists by the name of _werk_. If it was required to separate the silver, it was again fused, not in the first furnace, but in a particular refining furnace with a hearth of lixiviated ashes. This circumstance Pliny has not mentioned; perhaps it appeared to him unnecessary; perhaps he did not fully understand every part of the process; and were one inclined to say anything in his defence, modern travels and other works might be quoted, in which metallurgic operations are described in a manner no less imperfect. The produce obtained by the second fusion, called in German _treiben_ or _abtreiben_, was silver, and besides that half-vitrified lead, _glätte_, which in part falls into the hearth. This substance, called by Pliny _galena_, a word which denotes also _molybdæna_[507], was once more fused or revived, and then gave lead. In this manner were obtained three different productions, which were all used in commerce, namely, _stannum_, _argentum_ and _galena_, or revived lead, _plumbum nigrum_. These Pliny seems to have considered as component parts of lead ore; but not indeed according to the present signification[508]. Though it must be confessed that this passage of Pliny cannot be fully understood by any explanation, it proves to conviction that the _stannum_ of the ancients was neither our tin nor a peculiar metal, but the _werk_ of our smelting-houses. This was long ago remarked by those writers who were acquainted with metallurgy, of whom I shall here mention Agricola[509], Encelius[510], Fallopius[511], Savot[512], Bernia[513], and Jung[514]. The ancients used, as a peculiar metal, a mixture of gold and silver, because they were not acquainted with the art of separating them, and afterwards gave it the name of _electrum_. In the like manner they employed _werk_ or _stannum_, which was obtained almost in the same manner in the fusion of silver. In all probability it was employed before people became acquainted with the art of separating these two metals, and continued in use through habit, even after a method of separating them was discovered. If the ore subjected to fusion was abundant in silver, this mixture approached near to the noble metals; if poor in silver, it consisted chiefly of lead. When it consisted of silver and lead only, it was soft and ductile; but if other metals, difficult of fusion, such as copper, iron, or zinc, were intermixed, it was harder and more brittle, and in that case approached nearer to what the German silver refiners call _abzug_ and _abstrich_.