A dictionary of chemistry, on the basis of Mr. Nicholson's: in which the principles of the science are investigated anew, and its applications to the phenomena of nature, medicine, mineralogy, agriculture, and manufactures, detailed (Volume 2).

  • Ure, Andrew, 1778-1857.
Date:
1821
Catalogue details

Licence: Public Domain Mark

Credit: A dictionary of chemistry, on the basis of Mr. Nicholson's: in which the principles of the science are investigated anew, and its applications to the phenomena of nature, medicine, mineralogy, agriculture, and manufactures, detailed (Volume 2). Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    remarkable in its action on the gases. In M. de Saussure's experiments, the red-hot charcoal was plunged under mercury, and introduced, after it became cool, into the gas to be absorbed, without ever coming into contact with atmospherical air. Table of the Volumes of Gases absorbed by one volume of Gases. Charcoal. Meer- schaum. Adhesive slate. JAgnif. asbestus. Saxon hydvoph. Quartz. 10 Ammonia, 90 15 11.3 12.75 64 Muriatic acid, 85 — — — 17 — Sulphurous acid, 65 — — — 7.37 Sulphuretted hydrogen, 55 11.7 — — — — Nitrous oxide, 40 3.75 — — — Carbonic acid, 35 5.26 2. 1.7 10 0.6 defiant gas, 35 370 1.5 1.7 0.8 0.6 Carbonic oxide, 9.42 1.17 0.55 0.58 Oxygen, 9.25 1.49 0.7 0.47 0.6 0.45 Azote, 7.5 1.6 0.7 0.47 0.6 0.45 Oxycarburetted hydrogen £ 5.0 0.85 0.55 0.41 from moist charcoal, j Hydrogen, 1.75 0.44 0.48 0.31 0.4 0.37 The absorption was not increased by al- lowing the charcoal to remain in contact with the gases after 24 hours; with the ex- ception of oxygen, which goes on condens- ing for years, in consequence of the slow formation and absorption of carbonic acid. If the charcoal be moistened, the absorp- tion of all those gases that have not a very strong affinity for water, is distinctly di- minished. Thus boxwood charcoal, cool- ed under mercury, and drenched in water while under the mercury, is capable of ab- sorbing only 15 volumes of carbonic acid gas; although, before being moistened, it could absorb35 volumes of the same gas. Dry charcoal, saturated with any gas, gives out, on immersion in water, a quantity corres- ponding to the diminution of its absorbing power. During the absorption of gas by charcoal, an elevation of temperature takes place, proportional to the rapidity and amount of the absorption. The vacuum of the air-pump seems to possess the same influence as heat, in rendering charcoal capable of absorbing gaseous matter. A transferrer with a small jar containing a piece of charcoal was exhausted, and be- ing then plunged into a pneumatic trough, was filled with mercury. The charcoal was next introduced into a gas, and absorbed as much of it. as after having been ignited. As the rapid absorption of carbonic acid gas by charcoal can raise the thermometer 25°, so its extraction by the air-pump, sinks it 7.5°. Though charcoal possesses the highest absorbent power, yet it is common to all bodies which possess a certain degree of porosity, after they have been exposed to the action of the air-pump. Meerschaum, like charcoal, absorbs a greater bulk of rare than dense gas. Dried woods, linen threads, and silks, also absorb the gases. Of ammonia, hazel absorbs 100 volumes, mulberry 88, linen thread 68, silk 78; of carbonic acid, in the above order, 1.1, 0.46, 0.62, 1.1; of this gas, fir absorbed 1.1, and wool 1.7. The rate of absorption of different gas- es, appears to be the same, in all bodies of similar chemical properties. All the varieties of asbestus condense more carbo- nic acid gas, than oxygen gas; but woods condense more hydrogen than azote. Yet the condensations themselves in different kinds of asbestus, or wood, or charcoal, are very far from being equal. Ligniform asbestus absorbs a greater volume of car- bonic acid gas, than rock-cork; so does hy- drophane than the swimming quartz of St. Ouen, and the quartz of Vauvert; and the absorption of gases by boxwood charcoal, is much greater than by fir charcoal. These differences are not in the least altered, if, instead of equal volumes, equal weights of charcoal be employed. It is curious that a piece of solid charcoal absorbs 7$ vo- lumes, and the same reduced into fine powder absorbs only three volumes. The absorbing power of most kinds of charcoal increases as the specific gravity increases; and it is obvious, that the pores must be- come smaller and narrower with the in- crease of density. Charcoal from cork, of a specific gravity not exceeding 0.1, ab- sorbed no sensible quantity of atmospheric air. Charcoal from fir, sp. gr. 0.4, absorb- ed 4^ times its volume of atmospherical air; that from boxwood, sp. gr. 0.6. absorbed 7b of air; and pit-coal of vegetable origin from Kussiberg, sp. gr. 1.326, absorbed 10} times its volume of air. But, as the