2 BULLETIN" 37, TJ. S. DEPARTMENT OF AGRICULTURE. 
available for fertilizer purposes. There is one striking exception 
to this generalization. In the destructive distillation of coal for 
the preparation of gas and coke the nitrogen present in the coal is 
evolved, in part at least, as ammonia. This is easily recoverable 
and in the form of ammonium salts constitutes an important source 
of nitrogen for fertilizer purposes. 
The agronomic necessity which compels the use of nitrogenous fer- 
tilizers and the scarcity of nitrogenous compounds available for 
fertilizer purposes together make the nitrogen carriers of extremely 
great importance. 
The following materials constitute the present source of nitro- 
genous fertilizers: 
Chile saltpeter, or nitrate of soda. 
Artificial nitrates of soda, lime, and ammonia. 
Sulphate of ammonia. 
Fish scrap. 1 
Tankage. 
Dried blood. 
Cottonseed meal. 
SODIUM NITRATE. 
Sodium nitrate occurs naturally as an impregnation of earthy and 
saline material, known as caliche, on certain of the arid uplands of 
the Provinces of Tarapaca, Tacna, Antofagasta, and Atacama, in 
Chile. The names " Chile niter " and il Chile saltpeter" have been 
given this product because of its occurrence. 
The composition of caliche is given in Table I. 2 
Table I. — Analysis of caliche from Tarapacd Province, Chile. 
Constituent. 
Proportion. 
Constituent. 
Proportion. 
Per cent. 
60.97 
.73 
16.85 
4.56 
Per cent. 
1.33 
5.88 
Insoluble 
Water 
4.06 
5.64 
PRODUCTION AND CONSUMPTION OF SODIUM NITRATE. 
Of the sodium nitrate produced by the Chilean beds during the 
year 1911, 2,419,700 tons were exported, 1,827,089 tons to European 
countries 3 and 518,613 tons to the United States. In the United 
States 70,000 tons of this were used in agriculture. 
1 For a discussion of fish scrap see Bull. No. 2, U. S. Dept. Agr., "The Fish-scrap Fertilizer Industry 
of the Atlantic Coast/' 
2 Pennock, Losses of Combined Nitrogen. J. Ind, Eng. Chem. 4, 1 7 2 (1912). 
3 Exportations to Egypt are included in this amount. 
