4035. To Obtain Oxygen Gas

4035.    To Obtain Oxygen Gas. Heat in a retort or flask, finely powdered chlorate of potassa, mixed with about one-fourth its weight of black oxide of manganese. The gas must be collected by attaching a tube to the flask, and passed into a receiving bottle in a pneumatic trough. (See No. 4031 (Pneumatic Trough).)

Or: Take chloride of potassa, or red oxide of mercury, expose it to the heat of a spirit-lamp, in a suitable vessel, and collect the gas.

4036. Oxygen Gas from Bleaching Powder

4036.    Oxygen Gas from Bleaching Powder. Oxygen gas can be readily prepared by boiling bleaching powder (hypochlorite of lime) and nitrate of cobalt in a flask. Make a clear solution of the powder in water, put it into any convenient flask provided with a perforated cork and tube, and pour in a few drops of a solution of nitrate or chloride of cobalt, and set it to boil. The gas, as it is evolved, is collected in a receiving bottle. (See No. 4031 (Pneumatic Trough).)

4037. To Obtain Oxygen Without Heat

4037.     To Obtain Oxygen Without Heat. According to M. Boettger, oxygen can be obtained in a very pure state by employing binoxide of barium and peroxide of lead. Take equal parts of these substances and pour on weak nitric acid; the reaction commences immediately, and the gas can be collected as usual over cold water. (See No. 4031 (Pneumatic Trough).)

4038. Pure Oxygen for Inhalation

4038.    Pure Oxygen for Inhalation. Eliot recommends for the preparation of oxygen gas, to be used in medicine, the employment of a mixture of equal parts of peroxide of barium and peroxide of lead. By pouring dilute nitric acid upon these salts, there is a violent effervescence and a copious evolution of pure oxygen gas. For greater security, the gas may be afterwards washed in water. As very little heat is necessary, the operation can be performed in any stout bottle, thus dispensing with the usual retorts. For great purity, the first portion of gas that evolves should be allowed to escape, as it contains the air which was in the apparatus.

4039. To Obtain Oxygen on the Large Scale

4039. To Obtain Oxygen on the Large Scale. Nitre is exposed to a dull red heat in an iron retort or gun barrel; 1 pound of nitre thus yields about 1200 cubic inches of oxygen, slightly contaminated with nitrogen. (Ure.)

4040. Tests for Oxygen

4040.    Tests for Oxygen. It is distinguished from other gases by yielding nothing but pure water when mixed with twice its volume of hydrogen and exploded, or when a jet of hydrogen is burned in it. A recently extinguished taper, with the wick still red hot, instantly inflames when plunged into this gas. A small spiral piece of iron wire, ignited at the point and suddenly plunged into a jar of oxygen, burns with great brilliancy and rapidity.

4041. Hydrogen

4041.     Hydrogen. A gaseous element, colorless, combustible, and the lightest of ponderable bodies, its specific gravity being only .06935. It is a constituent part (about 12 per cent, by weight, and 67 per cent, by volume) of water. According to Dumas, "it is a gaseous metal, as mercury is a liquid metal." It forms an ingredient in all bodies that possess the power of burning with flame; it urns with a pale blue flame, and, in combination with carbon, constitutes the illuminating gas in general use. In contact with spongy platinum it inflames spontaneously; and, from its extreme lightness, is the best means employed for inflating balloons. It is one of the most useful elements in the material world. Hydrogen forms, with other bodies, a class of acids called hydrogen acids or hydracids. (See No. 3853.)