Nitrate of Soda or Chili Saltpetre

Nitrate of Soda or Chili Saltpetre is very extensively imported, and is sold on a basis of 95 per cent. nitrate, or '5 per cent. refraction'—i.e. not more than 5 per cent. of impurities. It is found native in several districts of South America in an impure state, and is rendered marketable by a process of solution and re-crystallising. Its action as a manure is comparable to that of nitrate of lime, nitrate of potash, or sulphate of ammonia. Its only valuable constituent is nitric acid, while in the other nitrates mentioned the base is also serviceable.