Theoretical organic chemistry / by Julius B. Cohen.

  • Julius B. Cohen
Date:
1902
Catalogue details

Licence: Public Domain Mark

Credit: Theoretical organic chemistry / by Julius B. Cohen. Source: Wellcome Collection.

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    with a condenser. The jacket prevents radiation from the boiling tube. It is provided with two windows of mica. The jacket is clamped on a gauze ring, supported on a square tray of asbestos placed upon a tripod. In Fig. 29 the lower part of the porcelain jacket and the asbestos tray are made transparent to show the position of the burners and the concentric rings of asbestos below the tray. The asbestos has a cir¬ cular hole in the centre, which admits the lower end of the boiling tube. Two asbestos chimneys are fixed upright at the diagonal corners of the tray to carry off heated air, and two burners are placed below the other two corners. The boiling- point of the solvent is first ascertained. The two burners under the tray are lighted, and the tem¬ perature regulated so that the liquid in the outer jacket boils briskly, whilst at the same time sufficient heat finds its way to the boiling tube, through the gauze ring outside the concentric screens of as¬ bestos, to keep the liquid in the inner tube in a state Fig. 29.—Beckmann’s apparatus. of steady ebullition. The temperature being constant it is noted, and a weighed pellet of the solid substance is dropped into the boiling tube through the condenser without interrupting the boiling. The boiling-point rises, and after a short time will remain stationary. The temperature is again noted. A second