Fig. 1.—Apparatus for chlorine experiments.
(2) Preparation.—Place one jar beneath the glass tube so that the latter’s orifice reaches nearly to the bottom, and slide the paper disc down until it covers the mouth of the jar C. On warming the glass flask gently with a spirit lamp or, if available, Bunsen gas flame, a greenish-yellow gas is evolved, and gradually expels the air from flask, tube, and jar, until this latter is filled with heavy chlorine. The warming is then interrupted whilst the one jar is removed, covered with a moist cardboard disc, and replaced by another. The heating again proceeds, and so on until each remaining jar is successively filled.
Fig. 2.—The unalterable postmark.
Chlorine Experiments (1).—Damp an addressed envelope, received through the post, by pressing between sheets of wet blotting-paper, and stand it in a jar of chlorine with the cover replaced (A, [Fig. 2]). The writing ink address will soon begin to fade and finally disappear, whilst the postmark, which has been impressed in indelible printing ink, remains unaltered. This reaction shows that chlorine possesses the valuable property of bleaching writing ink. It may be turned to account in removing stains from cloth by wetting the spoiled material first and then standing in a vessel containing the yellow gas ([Fig. 3]). The fabric must be quite damp, however, as bleaching only proceeds in the presence of moisture. Coloring matters, other than black ink, are readily removed by chlorine, as may be strikingly shown by steeping a wet rose blossom or bunch of violets in a jar of the gas ([Fig. 4]); the flowers assume a transparent waxy appearance, that will puzzle any spectator as to their real identity.
Fig. 3.—Removing stains from linen by means of chlorine.
Fig. 4.—The transparent rose.
Chlorine Experiments (2).—The energetic gas attacks many substances spontaneously. If thin blotting-paper be soaked in turpentine, drained, and dropped into a jar of chlorine, the oil takes fire at once, burning rapidly amid smoky black fumes. Metals are attacked just as readily as the inflammable oil of turpentine. Powdered antimony metal or iron filings shaken into a jar of chlorine scintillate brilliantly with the evolution of thick white fumes. Similarly Dutch metal leaf, used for gilding cheap picture frames, ignites in the gas; a salt of copper being precipitated to the bottom of the jar when the action has ceased.