BOOK XXXV. Lii. 183-184 



it. In Cyprus there is a white alum and another 

 sort of a darker colour, though the difference of 

 colour is only slight ; nevertheless the use made 

 of them is very different, as the white and hquid 

 kind is most useful for dying woollens a bright 

 colour whereas the black kind is best for dark or 

 sombre hues." Black alum is also used in cleaning * 

 gold. All alum is produced from water and shme, 

 that is, a substance exuded by the earth ; this 

 collects naturally in a hollow in winter and its 

 maturity by crystallisation is completed by the 

 sunshine of summer ; the part of it that separates 

 earhest is whiter in colour, It occurs in Spain, 

 Egypt, Armenia, Macedonia, Pontus, Africa, and the 

 islands Sardinia, Melos, Lipari '^ and StromboH ; the 

 most highly valued is in Egypt and the next best 

 in Melos. The alum of Meios also is of two kinds, 

 fluid '^ and dense. The test of the fluid kind is that 

 it should be of a hmpid, milky consistency, free from 

 grit when rubbed between the fingers, and giving 

 a sHght glow of colour ^ ; this kind is called in 

 Greek ' phorimon ' in the sense of ' abundant.' Its 

 adulteration can be detected/ by means of the juice 

 of a pomegranate, as this mixed with it does not 

 turn it black if it is pure. The other kind 9 is the 

 pale rough alum which may be stained with oak- 

 gall also, and consequently this is called ' paraphoron,' 



** Apparently the solid kind (potash-alum especially) in 

 solution. 



^ So MSS.; caloris (' heat ') is a change based on what is 

 probably a corruption in the text of Dioscorides. 



■^ That is, an alum supposedly free frora iron would, if it 

 contained iron, turn juice of pomegranate blaek. 



" Probably light yellow halotrichite (hydrated iron sulphate 

 with aluminium) and green vitriol (ferrous sulphate). 



397 



