172 CHYMISTRY APPLIED TO AGRICULTURE. 



The operation is very simple : a tub is filled with ashes, 

 upon which water is thrown till it stands upon the top ; in 

 the course of a few hours the water filtrates through the 

 ashes, and flows off by a vent in the bottom of the tub : 

 this ley should mark 10° or 12^ of the aerometer of Baume. 

 (Sp. gr. 1.075 to 1.091.) The first leaching does not ex- 

 haust the ashes entirely of all their alkali, and fresh water 

 is therefore passed through them till they contain nothing 

 soluble : this weak ley is added to new ashes, till it ac- 

 quires a suitable degree of strength. 



The leached ashes form an excellent manure for damp 

 or clayey soils; and it is used advantageously in the manu- 

 facture of black glass. 



Ley is most readily formed by using hot water, but I 

 have confined myself to pointing out the simplest means 

 for accomplishing the purpose, and those that require the 

 least apparatus. 



The ley is a solution of potash, which may be extracted 

 from it by evaporation r this process may be commenced 

 in a copper boiler, into which a very fine stream of the ley 

 should flow to replace that which evaporates : when the 

 liquor has acquired the consistency of honey, it should be 

 put into iron boilers to complete the operation. As the sub- 

 stance thickens, care must be taken to remove that por- 

 tion of it which adheres to the sides, and to stir the whole 

 carefully with iron spatulas. When the substance con- 

 geals and becomes solid upon being exposed to the air, it 

 is poured into casks and thrown into commerce under the 

 name of salts. 



The whole process is simple, and may be conducted 

 upon our farms without any difiiculty. The farmer can 

 appropriate to himself this branch of industry without in- 

 terrupting the usual course of his labors : broom, heath, 

 thistles, ferns, brambles, nettles, &c. may be collected 

 during the days when agricultural business cannot go on> 

 and in the dead season, and in the winter they may be 

 burned, and the ashes leached. 



I do not propose to any farmer to calcine the salts, to 

 reduce them to real potash, because he would need for this 

 purpose a reverberating furnace, and the process would be 

 one at variance with his customary employments. The 

 salts are already applied to numerous uses in the arts : 

 if the manufacture of them should become a domestic one, 

 there would very soon be establishments formed for con- 



