Dumas

Method of. A method for the determination of nitrogen. In a gla tube sealed at one end, place a layer (about I cm.) of dry, primary sodium carbonate or magnesite, then pure cupric oxid, afterwards a mixture of the substance with the cupric oxid; then again pure granular cupric oxid, and finally fill the tube with pure copper turnings. In the open extremity of the tube is placed a rubber cork, bearing a gas-delivery tube, which extends into a mercury bath. The back part of the combustion-tube, containing the carbonate, is heated first, to expel the air from all parts of the apparatus. A graduated cylinder, filled with mercury, is placed over the extremity of the exit-tube; into the tube containing mercury several cubic centimeters of concentrated pota ium hydroxid are introduced by means of a pipet. The metallic copper and the layer of cupric oxid in the anterior portion of the tube are first heated and then gradually the mixture. When the combustion is completed, heat is applied to another part of the sodium carbonate layer. The graduated ve el, containing pure nitrogen, is placed in a large cylinder of water, allowed to stand a short time until the temperature is equalized, when the volume of gas is read and the temperature of the surrounding air and the barometer height are noted. y J(h-w) I 1 0.00367 X 0.0012562 G the weight of the nitrogen volume in grams. V the absorbed volume in cubic centimeters, h the barometric pre ure, w the tension of aqueous vapor at the temperature i°C. 0.0012562 the weight, in grams, of l c.c. of nitrogen at o°C., and 760 mm. pre ure.