BOOK XII. 



IREVIOUSLY I have dealt with the methods of 

 ^i separating silver from copper. There now remains 

 the portion which treats of soUdified juices ; and 

 whereas they might be considered as alien to things 

 metallic, nevertheless, the reasons why they should 

 not be separated from it I have explained in the 

 second book. 



Solidified juices are either prepared from waters 

 in which nature or art has infused them, or they are 

 produced from the liquid juices themselves, or from stony minerals. Sagacious 

 people, at first observing the waters of some lakes to be naturally full of juices 

 which thickened on being dried up by the heat of the sun and thus became 

 solidified juices, drew such waters into other places, or diverted them 

 into low-lying places adjoining hills, so that the heat of the sun should 

 likewise cause them to condense. Subsequently, because they observed that 

 in this wise the solidified juices could be made only in summer, and then 

 not in aU countries, but only in hot and temperate regions in which it seldom 

 rains in summer, they boiled them in vessels over a fire until they began to 

 thicken. In this manner, at aU times of the year, in all regions, even the 

 coldest, solidified juices could be obtained from solutions of such juices, 

 whether made by nature or by art. Afterward, when they saw juices 

 drip from some roasted stones, they cooked these in pots in order to obtain 

 solidified juices in this wise also. It is worth the trouble to learn the pro- 

 portions and the methods by which these are made. 



I will therefore begin with salt, which is made from water either salty 

 by nature, or by the labour of man, or else from a solution of salt, or 

 from lye, likewise salty. Water which is salty by nature, is condensed and 

 converted into salt in salt-pits by the heat of the sim, or else by the heat 

 of a fire in pans or pots or trenches. That which is made salty by 

 art, is also condensed by fire and changed into salt. There should be as 

 many salt-pits dug as the circumstance of the place permits, but there should 

 not be more made than can be used, although we ought to make as much 

 salt as we can sell. The depth of salt-pits should be moderate, and the 

 bottom should be level, so that all the water is evaporated from the salt by 

 the heat of the sun. The salt-pits should first be encrusted with salt, so 

 that they may not suck up the water. The method of pouring or leading 

 sea-water into salt-pits is very old, and is still in use in many places. The 

 method is not less old, but less common, to pour weU-water into salt-pits, as 

 was done in Babylon, for which Plinj^ is the authority, and in Cappadocia, 

 where they used not only well-water, but also spring-water. In all hot 

 countries salt-water and lake-water are conducted, poured or carried into 

 salt-pits, and, being dried by the heat of the sun, are converted into 



