Prevention Of Leakage

When a liquid is distilled under reduced pressure, it is necessary that all joints in the apparatus should be air-tight. India-rubber stoppers cannot always be used for the still because this substance is attacked or dissolved by many organic liquids, and ordinary corks are seldom quite air-tight. Page,4 however, finds that all leakage may be effectually prevented by first exhausting the apparatus and then covering the cork with the ordinary liquid gum, sold in bottles (not gum arabic, which is apt to crack when dry). The gum may be conveniently applied with a brush and, if necessary, the application may be repeated several times.

Apparatus for fractional distillation under reduced pressure has also been described byLothar Meyer, Berichte, 1887, 20, 1834. H. Gautier, Bull. Soc. Ghim., 1889, 2, 675. H. Wislicenus, Berichte, 1890, 23, 3292. H. Schulz, ibid., 1890, 23, 3568. G. W. A. Kahlbaum, ibid., 1895, 28, 393. R. Steinlen, Chem. Zeit., 1898, 22, 157.

1 Loc. cit.

2 Rosanoff, Bacon and White, "A Rapid Laboratory Method of Measuring the Partial Vapour Pressures of Liquid Mixtures" (Apparatus), J. Amer. Chem. Soc, 1914, 36, 1806.

3 Hahn, "Fractionating Device," Ber., 1910, 43, 1725; J. Soc. Chem. Ind., 1910, 29, 842.

4 Page, "Cork versus Rubber,"Chem. News, 1902, 86, 162.