Saltpetre
(Nitrate of Potassium). A substance found in quantities as a natural product in Hindostan, and also much prepared artificially from heaps of organic remains allowed to decay in contact with Carbonate of Potassium. Its high price renders the use of it as manure impracticable, despite the good results that have attended its employment in experimental farming. Its value is due to its supplying both Potassium and Nitrogen in a form readily available to plants. Its place as a manure, in commerce, is supplied, in so far as yielding nitrogenous food, by Nitrate of Sodium, which is found in very extensive beds in South America, and can be sold, after being freed of excess of earthy substances, at a sufficiently low price to permit of its profitable employment by farmers. Saltpetre increases the yield of Cereals, and of Clover and other leguminous plants, and seems peculiarly to promote the growth of the green parts.