OK(iAMO MATTERS OF THE SOIL. :^Z4 



Ul.iiiL' ucilI from sugar has the following composition in 

 100 parts : 



Carbon, 67.1 



Hydrogen, 4.2 



Oxygen, 28.7 



100.0 



which corresponds to C,„ H^, O,^ H^O. 



Mulder considers that in the same manner there exist 

 various kinds of huinic acids and humin, differing from 

 each other by the elements of water, all of which may 

 be represented by the general for;iuila C^„ H„^ 0,„ nH^O. 

 Humic acid and humin from sugar, corresponding to 

 C40 H„^ 0,„ + 3H„0, have, according to Mulder, the fol- 

 lowing composition per cent : 



Carbon, 64 



Hydrogen, 4 



Oxygen, 32 



100 



Apocrenic and €renlc Acids. — In the acid liquid from 

 which ulmic or himiic acid has been separated, exist two 

 other acids which were first discovered by Berzelius in 

 the Porla spring in^ Sweden, and which bear the names 

 apocrenic acid and crenic acid respectively. By adiling 

 soda to the acid liquid until the hydrochloric acid is neu- 

 tralized, then acetic acid in slight excess, and lastly solu- 

 tion of acetate of copper (crystallized verdigris) as long 

 as a dirty-gray precipitate is formed, the apocrenic acid is 

 procured in combination with copper and ammonia. From 

 this salt the acid itself may be separated* as a brown, 

 gummy mass, which is easily soluble in water. Accord- 

 ing to Mulder it has the formula C^^ H,^ 0,^ + H^O, or, 

 in 100 parts, 



By i)recii)itatiuK the copper with sulphm-etted hydrogen. 



