yb PRACTICAL FARM CHEMISTRY. 



source of commercial nitrogen, and a very valuable 

 one besides. The chief point from which 



o??od^a. *^^^ nitrate is obtained is Ibique, Chili. 

 There is an export duty on it of ten dol- 

 lars per ton. Vast beds extend for two or three 

 hundred miles along the west coast of South Ameri- 

 ca. These beds are supposed to have been formed 

 by decomposing sea-weed. It is yet comparatively 

 little used in this country, and the present demand 

 for it is so limited that not a pound of the cheaper 

 grade — which strictly is the fertilizer nitrate — is im- 

 ported to the United States, while progressive 

 growers in Europe consume a hundred thousand 

 tons or more a year. 



The nitrate imported to this country is shipped 

 in bags holding about three hundred pounds each. 

 A chemically pure sample, as we have seen in Ninth 

 Chapter, or might again figure out from the chemi- 

 cal symbol Na NO3 and the table of atomic weights, 

 (see page 49) has 16.47 per cent of nitrogen. It 

 takes a pretty good sample of the salt as imported 

 to give us sixteen per cent, or 320 pounds to the ton. 

 The commercial value of this nitrogen, at the 

 present time, is fourteen and half cents per pound, 

 which would make a ton worth $46.60. It is said 

 that the article can be adulterated — for instance, 

 with additions of white sand, or of cheap potash 

 salts. . But every buyer can easily examine the stuff 

 upon its purity. See if it all perfectly dissolves in 

 water. If so, it is free from sand. Then taste the 

 solution, and if this has no distinct salty taste, you 

 may be sure there is no cheap potash salt in it. 



Now, when we are thus assured of having the 

 genuine article, we may also feel certain that every 

 ounce of this nitrogen is ready for immediate use by 



