niter

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A white, gray, or colorless mineral of potassium nitrate, KNO₃, used in making gunpowder. Also called saltpeter.

Century Dictionary and Cyclopedia

1. n. A salt (KNO₃), also called saltpeter, and in the nomenclature of chemistry potassium nitrate. It is formed in the soil from nitrogenous organic bodies by the action of microbes, and crystallizes upon the surface in several parts of the world, and especially in the East Indies. In some localities where the conditions are favorable it is prepared artificially from a mixture of common mold, or porous calcareous earth containing potash, with animal and vegetable remains containing nitrogen. Under proper conditions of heat and moisture the nitrogen of the decaying organic matter is oxidized to nitric acid, which combines with potash and lime, forming niter and calcium nitrate. This is afterward dissolved in water and purified. At present it is chiefly prepared from sodium nitrate and potassium chlorid by double decomposition. It is a colorless salt, with a saline taste, and crystallizes in six-sided prisms. It is used somewhat as an antiseptic and as an oxidizing agent, but its most common use in the arts is in the making of gunpowder; it also enters into the composition of fluxes, is extensively employed in metallurgy, and is used in dyeing. In medicine it is prescribed as diaphoretic and diuretic. The substance called niter by the ancients was not potassium nitrate, but either sodium carbonate, more or less mixed with salt and other impurities, or potassium carbonate, chiefly the former, since niter is usually spoken of as having been obtained from the beds of salt lakes, where the alkali must have been soda, this heing a mode of occurrence peculiar to soda and not to potash. But the niter which the ancients speak of as having been obtained by leaching wood-ashes was more or less pure potassium carbonate. It was not until the early part of the eighteenth century that soda and potash began to be clearly recognized as distinct substances; and it was considerably later in the century before the chemical relations of the two alkalis were understood. See saltpeter, soda, and potash.
2. n. The word niter (in its Hebrew, Greek, and Latin forms) was used in early times to signify any kind of saline efflorescence, and therefore included a number of substances now recognized as distinct. The ‘niter’ of the Old Testament scriptures was obviously natron in the sense of naturally occurring carbonate of soda (from Egypt). The ‘nitrum’ mentioned by Pliny, which gave off a strong smell on being sprinkled with lime, must have been a salt of ammonium, probably the chlorid; but potassium nitrate (the niter or saltpeter of the present age), and also calcium nitrate, potassium carbonate, sodium chlorid, magnesium sulphate, and the sulphates of zinc, iron, and copper (later distinguished as metallic vitriols) were probably more or less confounded under the general name.

Wiktionary

1. n. US, chemistry A mineral form of potassium nitrate used in making gunpowder.

GNU Webster's 1913

1. n. (Chem.) A white crystalline semitransparent salt; potassium nitrate; saltpeter. See saltpeter.
2. n. (Chem.), obsolete Native sodium carbonate; natron.

WordNet 3.0

1. n. (KNO3) used especially as a fertilizer and explosive