Nitrogen

(ni' '-tro-jen). X 14; quantivalence I, III, v. One of the nonmetaliic elements, gaseous at ordinary temperatures. It is a component element of albumins, proteids, urea, and other organic substances, of alkaloids, ammonia, and its derivatives, and many other inorganic substances. It forms about 79 per cent, of the air, and is most active in combination with oxygen. The French call it azote. The salts of nitric acid are called nitrates, those of nitrous acid nitrites. See Elements, Table of A description of various methods for detecting nitrogen is appended: Kjeldahl's Method; the substance is di olved by heating it with concentrated sulphuric acid. Pota ium permanganate is then added until a distinctly green color appears. The liquid is diluted th water and the ammonia is expelled by boiling h sodium hydroxid. Limprecht's Method, a thod of determining the nitrogen of nitro-comnds and nitroso-compounds indirectly by means of titrated solution of stannous chlorid. Will and arrentrap's Method; two parts of calcium hydrate added to one part of an aqueous solution of e sodium hydroxid; the mixture is evaporated and ignited. The weighed, finely-pulverized substance is mixed with soda-lime (about ten parts) and the mixture is placed in a combustion -tube, about 30 cm. long, which is filled in with soda-lime. In the open extremity of the tube is placed a rubber stopper bearing a bulb-apparatus containing dilute hydrochloric acid. The anterior portion of the bulb is first heated in the furnace; then, that containing the mixture. That all of the ammonia may be carried into the bulb, j air is conducted through the tube, after breaking off the I point. The ammonium chlorid in the hydrochloric acid is precipitated as ammonio-platinum chlorid by means of platinic chlorid, and the residual platinum is weighed. One atom of platinum corresponds to two molecules of or two atoms of nitrogen. N., Gaseous Oxid of. See Nitrous Oxid.