234 BOOK VII. 



and a certain white schist 14 . But lead, its ashes, red-lead, ochre, and 

 litharge, are more efficacious for ores which melt easily ; hearth-lead for 

 those which melt with difficulty ; and galena for those which melt with 

 greater difficulty. To the second order belong iron filings, their slag, sal 

 artificiosus, argol, dried lees of vinegar 15 , and the lees of the aqua which separates 

 gold from silver 16 ; these lees and sal artificiosus have the power of penetrating 

 into ore, the argol to a considerable degree, the lees of vinegar to a greater 

 degree, but most of all those of the aqua which separates gold from silver ; 

 filings and slags of iron, since they melt more slowly, have the power of heat- 

 ing the ore. To the third order belong pyrites, the cakes which are melted 

 from them, soda, its slags, salt, iron, iron scales, iron filings, iron slags, vitriol, 

 the sand which is resolved from stones which easily melt in the fire, and 

 tophus ; but first of all are pyrites and the cakes which are melted from it, for 

 they absorb the metals of the ore and guard them from the fire which con- 

 sumes them. To the fourth order belong lead and copper, and their relations. 

 And so with regard to fluxes, it is manifest that some are natural, others 

 fall in the category of slags, and the rest are purged from slag. When we 



" buildings, because it is perishable and soft. Still, however, there are some places which 

 " have no other, as Carthage, in Africa. It is eaten away by the emanations from the 

 " sea, crumbled to dust by the wind, and washed away by the rain." In fact, tophus was 

 a wide genus among the older mineralogists, Wallerius (M 'editationes Physico Chemicae De 

 Origine Mundi, Stockholm, 1776, p. 186), for instance, gives 22 varieties. For the purposes 

 for which it is used we believe it was always limestone of some form. 



lt Saxum fissile album. (The Interpretatio gives the German as schifer) Agricola 

 mentions it in Bermannus (459), in De Natura Fossilium (p. 319), but nothing definite 

 can be derived from these references. It appears to us from its use to have been either a 

 quartzite or a fissile limestone. 



16 Argol (Feces vini siccae," Dried lees of wine." Germ, trans, gives die wein heffen, 

 although the usual German term of the period was weinstein). The lees of wine were the 

 crude tartar or argols of commerce and modern assayers. The argols of white wine are white, 

 while they are red from red wine. The white argol which Agricola so often specifies would 

 have no special excellence, unless it may be that it is less easily adulterated. Agricola (De Nat. 

 Fos., p. 344) uses the expression " Fex vini sicca called tartarum" one of the earliest 

 appearances of the latter term in this connection. The use of argol is very old, for 

 Dioscorides (ist Century A.D.) not only describes argol, but also its reduction to impure 

 potash. He says (v, 90) : " The lees (tryx) are to be selected from old Italian wine ; if not, 

 from other similar wine. Lees of vinegar are much stronger. They are carefully dried and 

 then burnt. There are some who burn them in a new earthen pot on a large fire until they 

 are thoroughly incinerated. Others place a quantity of the lees on live coals and pursue 

 the same method. The test as to whether it is completely burned, is that it becomes white 

 or blue, and seems to burn the tongue when touched. The method of burning lees of 

 vinegar is the same. ... It should be used fresh, as it quickly grows stale ; it should 

 be placed in a vessel in a secluded place." Pliny (xxm, 31) says : " Following these, come 

 the lees of these various liquids. The lees of wine (vini faecibus) are so powerful as to be 

 fatal to persons on descending into the vats. The test for this is to let down a lamp, which, 

 if extinguished, indicates the peril. . . . Their virtues are greatly increased by the 

 action of fire." Matthioli, commenting on this passage from Dioscorides in 1565, makes 

 the following remark (p. 1375) : " The precipitate of the wine which settles in the casks of 

 the winery forms stone-like crusts, and is called by the works-people by the name tartarum." 

 It will be seen above that these lees were rendered stronger by the action of fire, in which case 

 the tartar was reduced to potassium carbonate. The weinstein of the old German metal- 

 lurgists was often the material lixiviated from the incinerated tartar. 



Dried lees of vinegar (siccae feces aceti ; Interpretaltio, die heffe des essigs). This would 

 also be crude tartar. Pliny (xxm, 32) says : " The lees of vinegar (faex aceti) ; owing to the 

 " more acrid material are more aggravating in their effects. . . . When combined with 

 " melanthium it heals the bites of dogs and crocodiles." 



16 Dried lees of aqua which separates gold and silver. (Siccae feces aquarum quae aurum 

 ab argento secernunt. German translation, Der scheidwasser heffe). There is no pointed 

 description in Agricola's works, or in any other that we can find, as to what this material 

 was. The " separating aqua " was undoubtedly nitric acid (see p. 439, Book X). There 



