MATERIAL RESOURCES OF LIFE. 343 



The chief commodities bearing nitrogen are nitre or saltpetre (potas- 

 sium or sodium nitrate) and ammonia. In Hindostan, the rich soil-mould, 

 warm and alkaline, becomes thinly crusted with nitrate, which is gathered 

 and brought to market as East India nitre. G-unpowder, gun-cotton and 

 nitro-glycerine, as well as chemical products, are made with it. In the war 

 of 1812, America was thrown upon her own sources for gunpowder mate- 

 rial, and enough nitre was found in the cave deposits of the Southwestern 

 States. Then France was hemmed in by hostile armies, and had neither 

 nitre nor cave-deposits, but it was after the work of "Lavoisier of Immortal 

 Memory," and the government put trust in chemistry. BerthoUet and the 

 rest soon justified the trust in the perfection of the "nitre plantations"— beds 

 of farm -refuse with wood-ashes exposed to the air. 



These products, soil-nitre and compost nitre, and the ammonia obtained 

 as a by-product in the manufacture of illuminating gas, serve their several 

 purposes in the arts and applications of man, but their limited quantities do 

 not warrant their addition to the soil for the increased growth of food. 

 JSTow, unlike these common supplies, the earth possesses a special resource for 

 nitrogen in combination, anomalous in being fully mineralized and remark- 

 able in being both concentrated and extensive, a chain of mines full of nitre. 

 On the Pacific coast of South America, extending from the fourth to the 

 fortieth degree of south latitude, about 2,400 miles along the slope of the 

 Andes to the sea, in Bolivia, Peru, and part of Chili, there has been found a 

 line of deposits of sodium nitrate, the "Peruvian nitre." The beds arc of 

 variable thickness, covered by one to ten yards' depth of earth and half- 

 formed sandstone. The dry soil of most of this rainless country is pervaded, 

 in some degree, with this deposit. The mummied remains of the old Peru- 

 vian people are embalmed with it by the earth in which they were buried ; 

 and its crystals glisten on those ghastly relics which were presented in the 

 Peruvian department of the Centennial Exhibition, and those brought to this 

 country by Dr. Steere. It has been estimated that in the province of Tara- 

 paca, within fifty leagues square, the quantity of the nitre is not less than 

 63,000,000 tons. The appropriation of this vast resource has been taken up 

 rather slowly, but has much increased for ten or twelve years past. Vessels 

 laden with it go to the coasts of manufacturing countries. At Glasgow the 

 works devoted to the production of ordinary saltpetre from the nitre of Peru 

 extend over acres of ground. In 1868, 100,000,000 pounds were used in 

 Great Britain. As yet, it has been applied to the nourishment of crops only 

 to a limited extent. But this seems to be its chief destination, and for this 

 use it lies in the earth, a vast mine of wealth, for the disposal of coming 

 generations. When multiplied population puts the sustaining of the earth 

 really to the test, this fund of sustenance on the Peruvian coast must come 

 to outweigh in value the gold and silver mines of the California coast. 



Of the several nitrogen compounds which nourish plants, ammonia yields 

 the most immediately satisfactory results. And of this fertilizing material, 

 some wellnigh mineralized deposits must be counted in with the earth's 



