546 BOOK XII. 



salt.^ While the salt-water contained in the salt-pits is being heated by the sun, 

 if they be flooded with great and frequent showers of rain the evaporation is 

 hindered. If this happens rarely, the salt acquires a disagreeable^ flavour, and 

 in this case the salt-pits have to be. filled with other sweet water. 



Salt from sea-water is made in the following manner. Near that part 

 of the seashore where there is a quiet pool, and there are wide, level plains 

 which the inundations of the sea do not overflow, three, four, five, or six 

 trenches are dug six feet wide, twelve feet deep, and six hundred feet long, 

 or longer if the level place extends for a longer distance ; they are two hundred 

 feet distant from one another ; between these are three transverse trenches. 

 Then are dug the principal pits, so that when the water has been raised from 

 the pool it can flow into the trenches, and from thence into the salt-pits, 

 of which there are numbers on the level ground between the trenches. The 

 salt-pits are basins dug to a moderate depth ; these are banked round with 

 the earth which was dug in sinking them or in cleansing them, so that between 

 the basins, earth walls are made a foot high, which retain the water let into 

 them. The trenches have openings, through which the first basins receive 

 the water ; these basins also have openings, through which the water flows 

 again from one into the other. There should be a slight fall, so that the 

 water may flow from one basin into the other, and can thus be replenished. 

 All these things having been done rightly and in order, the gate is raised that 

 opens the mouth of the pool which contains sea-water mixed with rain-water 

 or river-water ; and thus all of the trenches are filled. Then the gates of the 

 first basins are opened, and thus the remaining basins are filled with the 

 water from the first ; when this salt-water condenses, all these basins are 

 incrusted, and thus made clean from earthy matter. Then again the first 

 basins are filled up from the nearest trench with the same kind of water, 

 and left until much of the thin liquid is converted into vapour bj' the heat 

 of the sun and dissipated, and the remainder is considerably thickened. Then 

 their gates being opened, the water passes into the second basins ; and 

 when it has remained there for a certain space of time the gates are opened, 

 so that it flows into the third basins, where it is all condensed into salt. 

 After the salt has been taken out, the basins are filled again and again with 

 sea-water. The salt is raked up with wooden rakes and thrown out with 

 shovels. 



Salt-water is also boiled in pans, placed in sheds near the wells from 

 which it is drawn. Each shed is usually named from some animal or other 

 thing which is pictured on a tablet nailed to it. The walls of these sheds 

 are made either from baked earth or from wicker work covered with thick 



^The history of salt-making in salt-pans, from sea-water or salt springs, goes further 

 back than human records. From an historical point of view the real interest attached to 

 salt lies in the bearing which localities rich in either natural salt or salt springs, have had 

 upon the movements of the human race. Many ancient trade routes have been due to 

 them, and innumerable battles have been fought for their possession. Salt has at times 

 served for currency, and during many centuries in nearly every country has served as a 

 basis of taxation. These subjects do not, however, come within the scope of this text. 

 For the quotation from Pliny referred to, see Note 14 below, on bitumen. 



^The first edition gives gniviurem, the latter editions gratiorem, which latter would 

 have quite the reverse meaning from the above. 



