[851] The gold thus tested was called “obrussum,” “obryzum,” or “obrizum,” from the Greek ὄβρυζον, meaning “pure gold.”
[852] See B. xviii. c. 23, where he calls the chaff used for this purpose by the name of “acus.”
[853] The present mode of assaying the precious metals, is by fusing them upon a cupel with lead.
[854] For which purpose, lead was used, no doubt, in drawing the lines in the MSS. of the ancients. See Beckmann’s Hist. Inv. Vol. II. p. 339. Bohn’s Ed.
[855] This is far surpassed at the present day, its malleability being such that it may be beaten into leaves not more than one two hundred and eighty thousandth of an inch in thickness, and its ductility admitting of one grain being drawn out into five hundred feet of wire. For further particulars as to the gold leaf of the ancients, and the art of gilding, as practised by them, see Beckmann’s Hist. Inv. Vol. II. p. 391, et seq. Bohn’s Edition.
[857] He alludes to what are now known as pepitas, oval grains of river-gold. “Striges” is the reading in the Bamberg MS., “strigiles” in the former editions.
[858] “Massa.” As we should say at the present day, “nuggets.”
[859] “Ramentum.”
[860] The contrary is now known to be the case; gold is sometimes, though rarely, found in an oxidized state.