574 



BOOK XII. 



A — Tunnel. B — Bucket. C — Pit. 



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 Ught 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 

 bimches of grapes. 



" Misy when it eflBoresces 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. 



