70 ON THE ORIGIN AND ACTION OF HUMUS. 



properties, effect, in most cases, the same kind of 

 transformations. 



Hydrocyanic acid {^prussic acid)* and water con- 

 tain the elements of carbonic acid, ammonia^ urea, 

 cyanuric acid, cyanilic acid, oxalic acid, formic acid, 

 melam, ammelin, melamin, azulmin, mellon, hydro- 

 mellonic acid, allantoin, (^c.f It is well known, that 

 all these very different substances can be obtained 



* Cyanogen is considered by Liebig as a compound base, and as 

 such uniting with oxygen, hydrogen, and most other nonmetaHic 

 elements and with the metals. Cyanogen gas, or bicarburet of nitro- 

 gen, is a compound of nitrogen and carbon, and was named from its 

 affording a blue color and being an ingredient of Prussian blue. For 

 the method of obtaining it, &c., see Webster's Chemistry, 3d edition, 

 p. 219. 



With hydrogen it constitutes hydrocyanic acid. 



t Carbonic acid is a gaseous compound of I equivalent of carbon, 

 and 2 equivalents of oxygen, represented thus, C -f- 20 or c? the two 

 dots denoting the two of oxygen. 



Ammonia consists of 3 equivalents of hydrogen, and 1 equivalent of 

 nitrogen, represented thus, N -f- 3H, or NH3. 



Urea contains the elements of cyanate of ammonia (NH4 O -f- C4 NO), 

 and exists in urine, from which it is obtained in colorless, transparent 

 crystals. 



Cyanuric acid is a product of the decomposition of chloride of cyan- 

 ogen, of urea, &c. It is called a tribasic acid, and its hydrate is thus 

 represented, Cys O3 + 3HO. 



Oxalic acid is a solid acid obtained from several plants, particularly- 

 of the genera oxalis, rumex, &c. combined with potassa in roots, and 

 with lime in several kinds of lichens. Oxalate of lime is found in 

 urinary calculi. It is represented thus, 2CO -|- O (2 equivalents of 

 carbonic oxide -{- I oxygen). The so-called Essential salt of lemons is 

 a binoxalate of potash. It is poisonous. 



Formic acid, obtained from ants, hence its name. It is now obtained 

 from sugar and other vegetable substances. Represented by C2 HO3. 



Melam is a compound of C12 Nu Hg; it is a white powder insoluble 

 in water, and, by the action of acids, converted into cyanuric acid and 

 ammonia. 



jimmelin, a saline base, represented thus, Cs N5 H5 O2, a product of 

 the decomposition of melam by acids and alkalies. 



Melamin, a saline base, product of the decomposition of melam, 

 Cs Ns He. Decomposed by acids into ammonia and ammelid or 

 ammelin. 



Jlzulmen, the base of azulmic acid, obtained by the decomposition 

 of cyanogen. The acid is Cs H4 N4 O4. 



Mellon, a compound base, a yellow powder. Decomposed into 3 

 volumes cyanogen and 1 volume nitrogen gas. Ce N4. 



Hydromellonic acid is Cs N4 -|- H. 



Mlantoinc or allantoic acid occurs in the allantoic fluid of the cow ; 

 it is formed when uric acid is boiled in water with peroxide of lead. 

 It is C4 Hg N2 O3 or 2Cy -f 3H0. 



