In hot regions or in summer, it is poured into out-of-door pits which have
been dug to a certain depth, or else it is extracted from shafts by pumps
and poured into launders, through which it flows into the pits, where it is
condensed by the heat of the sun. In cold regions and in winter these vitriol
waters are boiled down with equal parts of fresh water in rectangular leaden
caldrons ; then, when cold, the mixture is poured into vats or into tanks,
which Pliny calls wooden fish-tanks. In these tanks light cross-beams are
fixed to the upper part, so that they may be stationary, and from them hang
ropes stretched with little stones; to these the contents of the thickened
solutions congeal and adhere in transparent cubes or seeds of vitriol, like
bunches of grapes.
" Misy when it effloresces in no great quantity from the others is like a kind of pollen, other" wise it is nodular. Melanteria sometimes resembles wool, sometimes salt."
The sum and substance, therefore, appears to be that misy is a yellowish material,
possibly ochre, and sory a blackish stone, both impregnated with vitriol. Chalcitis is a
partially decomposed pyrites : and melanteria is no doubt native vitriol. From this last
term comes the modern melanterite, /'native hydrous ferrous sulphate. Dana (System of
Mineralogy, p. 964) considers misy to be in part copiapite—basic ferric sulphate—but
any such part would not come under Agricola's objection to it as a source of vitriol. The
disabilities of this and chalcitis may, however, be due to their copper content.