2;>0 now ( nop,; fkkd. 



which are acted upon Ly the carbonates of potash, soda, 

 and lime, that become ini^redients of the soil by tlie 

 solution of rocks, or by carbonate of ammonia brought 

 down from the at<nosphere or produced by decay of ni- 

 trogenous matters, acquire solubility, an<l are, in fact, 

 acids ; and these portions ai-e acids in combination (salts), 

 and not in the free state. 



The Salts of the Humus Acids that may exist in the 

 soil, \\z., the ulmates, liumates, apocrenates, and crenatos 

 of potash, soda, ammonia, lime, magnesia, iron, manga- 

 nese, and alumina, require notice. 



The ulmates and humates agree closely in their charac- 

 ters so far as is known. 



The lUmates and humates of the alkalies (potash, soda, 

 and ammonia) Vive freely soluble in water. They are foimed 

 when the alkalies or their carbonates come in contact 1st, 

 with the ulmic and humic acids themselves ; 2d, with the 

 ulmates and humates of lime, magnesia, iron, and manga- 

 nese; and 3d, by the action of the alkalies and their car- 

 bonates on humin and ulmin. Their solutions are yellow 

 or brown. 



The ulmates and hiimates of lime, magnesia, iron, man- 

 ganese, and alumina, are insoluble, or bid very slightly 

 ■soluble in water. 



From ordinary soils where these earths and oxides pre- 

 dominate, water removes but traces of humates and 

 ulmates. 



From peat, garden earth, and Icafmould, Avhich contain 

 excess of the humic and ulmic acids, and carbonate of 

 ammonia resulting from the decay of nitrogenous matters, 

 water extracts a perceptible amount of these acids render- 

 ed soluble by the alkali. 



There appear to exist double salts of humic acid and of 

 ulmic acid, i. e., salts containing the acid combined with two 

 or more bases. By adding solutions of compounds (e.g., 

 .sulphates) of lime, magnesia, iron, manganese, and alumina 



