BOOK X\X1\ . xxii. 101-104 



part of the substance being separated out by the 

 flames and the blast and becoming attached in 

 proportion to its degree of Hghtness to the roof- 

 chambers and side-walls of the furnaces, the thinnest 

 being at the very mouth of the furnace, which the 

 flames have belched out ; it is called ' smoky cadmea ' 

 from its burnt appearance and because it resembles 

 hot white ash in its extreme Hghtness. The part 

 inside is best, hanging from the vaults of the roof- 

 chamber, and this consequently is designated ' grape- 

 cluster cadmea ' : this is heavier than the preceding 

 kind but Hghter than those that foHow — it is of two 

 colours, the inferior kind being the colour of ash and 

 the better the colour of pumice — and it is friable, 

 and extremely useful for making medicaments for 

 the eyes. A third sort is deposited on the sides of 

 furnaces, not having been able to reach the vaults 

 because of its weight; this is caHed in Greek 

 ' placitis,' ' caked residue,' in this case by reason 

 of its flatness, as it is more of a crust than pumice, 

 and is mottled inside ; it is more useful for itch- 

 scabs and for making wounds draw together into a 

 scar. Of this kind are formed two other varieties, 

 onychitis which is almost blue outside but inside Hke 

 the spots of an onyx or layered quartz, and ostracitis 

 ' sheH-Hke residue ' which is aU black and the dirtiest 

 of any of the kinds ; this is extremely useful for 

 wounds. AH kinds of cadmea (the best coming from 

 the furnaces of Cyprus) for use in medicine are 

 heated again on a fire of pure charcoal and. when it 

 has been reduced to ash, if being prepared for plasters 

 it is quenched with Amminean wine, but if intended 

 for itch-scabs with vinegar. Some people pound it 

 and then burn it in earthenware pots, wash it in 



203 



