156. The Official Volumetric Method.—This process may be used for nitrogen in any form of combination.[133]
The apparatus and reagents needed are as follows:
Combustion tube of best hard Bohemian glass, about sixty-six centimeters long and 12.7 millimeters internal diameter.
Azotometer of at least 100 cubic centimeters capacity, accurately calibrated.
Sprengel mercury air-pump.
Small paper scoop, easily made from stiff writing paper.
Coarse cupric oxid.—To be ignited and cooled before using.
Fine cupric oxid.—Prepared by pounding ordinary cupric oxid in a mortar.
Metallic copper.—Granulated copper, or fine copper gauze, reduced and cooled in a current of hydrogen.
Sodium bicarbonate.—Free from organic matter.