BOOK XXXIV. XXVIII. 116-XXX. 120 



also obtained by scraping a copper ore of which we 

 shall now speak. 



XXIX. Chalcitis, ' copper-stone,' is the name of chaicUis. 

 an ore," that from which copper also, besides cadmea, 



is obtained by smelting. It differs from cadmea 



because the latter is quarried above ground, from 



rocks exposed to the air, whereas chalcitis is obtained 



from underground beds, and also because chalcitis 



becomes immediately friable, being of a soft nature, 



80 as to have the appearance of congealed down. 



There is also another ditference in that chalcitis 



contains three kinds of mineral, copper, rnisy ^ and 



sori,^ each of which we shall describe in its place ; §§ 120, 121. 



and the veins of copper in it are of an oblong shape. 



The approved variety of chalcitis is honey coloured, 



and streaked with fine veins, and is friable and not 



stony. It is also thought to be more useful when 



fresh, as when old it turns into sori. It is used for 



growths in ulcers, for arresting haemorrhage and, 



in the form of a powder, for acting as an astringent 



on the gums, uvula and tonsils, and, applied in wool, 



as a pessary for affections of the uterus, while with 



leek juice it is employed in plasters for the genitals. 



It is steeped for forty days in vinegar in an earthen- 



ware jar, covered with dung, and then assumes the 



colour of saffron ; then an equal weight of cadmea is 



mixed with it and this produces the drug called 



psoricon or cure for itch. If two parts of chalcitis 



are mixed with one of cadmea this makes a stronger 



form of the same drug, and moreover it is more violent 



if it is mixed in vinegar than if in wine ; and when 



roasted it becomes more eflfective for all the same 



purposes. 



XXX. Egyptian sori is most highly commended, soru 



215 



