The decomposition of the fixed alkalies and alkaline earths / H. Davy.

  • Humphry Davy
Date:
1902
Catalogue details

Licence: In copyright

Credit: The decomposition of the fixed alkalies and alkaline earths / H. Davy. Source: Wellcome Collection.

    35/60 (page 31)
    the results doubtful; and the proportions from the weight of the oxygene absorbed are more to be depended on. In the experiments in which the processes of weighing were most speedily performed, and in which no alkali adhered to the tube, the basis of potash gained nearly 2 parts for 10, and that of soda between 3 and 4 parts. 'I’he results of the decomposition of water by the bases of the alkalies were much more readily and perfectly obtained than those of their combustion. To check the rapidity of the process, and, in the case of potash, to prevent any of the basis from being dis- solved, I employed the amalgams with mercury. I used a known weight of the bases, and made the amalgams under naphtha, using about tw'o parts of mercury in volume to one of basis. In the first instances I placed the amalgams under tubes filled with naphtha, and inverted in glasses of naphtha, and slowly admitted water to the amalgam at the bottom of the glass; but this precaution I soon found unnecessary, for the action of the water was not so intense but that the hydrogene gas could be wholly collected. I shall give an account of the most accurate experi- ments made on the decomposition of water by the bases of potash and soda. I-n an experiment on the basis of potash conducted with every attention that I could pay to the minutiee of the operations, hydrogene gas, equal in volume to 298 grains of mercury, were disengaged by the action of .08 grains of the basis of potash which had been amalgamated with about 3 grains of mercury. The thermometer at the end of the process indicated a temperature of 56° Fahrenheit, and the barometer an atmospheric pressure equal to 29.6 inches.