Theoretical organic chemistry / by Julius B. Cohen.

  • Cohen, Julius B. (Julius Berend), 1859-1935.
Date:
1902
Catalogue details

Licence: Public Domain Mark

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

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    densities. In the case of permanent gases, the gas is weighed in a large globe according to the method of Regnault. Victor Meyer’s method and Hofmann’s method consist in ascertaining the volume occupied by a given weight of the vaporised substance. According to Dumas’ method, the weight of substance occupying a given volume is deter¬ mined. Regnault’s Me¬ thod.—The method is only used for permanent gases, and has a very limited application in organic chemistry. It consists in counterpois¬ ing a large globe, first evacuated, and then filled with the gas and finally with hydrogen, against a similar globe having the same capa¬ city, the difference be¬ ing adjusted by weights. The second globe is em¬ ployed to neutralise the effects due to varying temperature, pressure, and moisture, which would greatly alter the .buoyancy of the single globe, whereas when Fig. 22. —The Victor-Meyer vapour density apparatus. two globes are em- changes ployed, the affect them in the same way, and do not interfere with the actual weight of the gases. Air Displacement, or Victor Meyer’s Method. method is universally employed ; for, whilst yielding -This fairly