546

BOOK XII.

salt . 1 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 ishindered. If this happens rarely, the salt acquires a disagreeable 2 flavour, andin 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 partof the seashore where there is a quiet pool, and there are wide, level plainswhich the inundations of the sea do not overflow, three, four, five, or sixtrenches 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 hundredfeet distant from one another ; between these are three transverse trenches.Then are dug the principal pits, so that when the water has been raised fromthe 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. Thesalt-pits are basins dug to a moderate depth ; these are banked round withthe earth which was dug in sinking them or in cleansing them, so that betweenthe basins, earth walls are made a foot high, which retain the water let intothem. The trenches have openings, through which the first basins receivethe water; these basins also have openings, through which the water flowsagain from one into the other. There should be a slight fall, so that thewater 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 thatopens the mouth of the pool which contains sea-water mixed with rain-wateror river-water ; and thus all of the trenches are filled. Then the gates of thefirst basins are opened, and thus the remaining basins are filled with thewater from the first; when this salt-water condenses, all these basins areincrusted, and thus made clean from earthy matter. Then again the firstbasins 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 by the heatof the sun and dissipated, and the remainder is considerably thickened. Thentheir gates being opened, the water passes into the second basins; andwhen 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 withsea-water. The salt is raked up with wooden rakes and thrown out withshovels.

Salt-water is also boiled in pans, placed in sheds near the wells fromwhich it is drawn. Each shed is usually named from some animal or otherthing which is pictured on a tablet nailed to it. The walls of these shedsare made either from baked earth or from wicker work covered with thick

J The history of salt-making in salt-pans, from sea-water or salt springs, goes furtherback than human records. From an historical point of view the real interest attached tosalt lies in the bearing which localities rich in either natural salt or salt springs, have hadupon the movements of the human race. Many ancient trade routes have been due tothem, and innumerable battles have been fought for their possession. Salt has at timesserved for currency, and during many centuries in nearly every country has served as abasis 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 graviorem, the latter editions gratiorem, which latter wouldhave quite the reverse meaning from the above.