A manual of materia medica and therapeutics : including the preparations of the British pharmacopoeia, and many other approved medicines / by J. Forbes Royle and Frederick W. Headland.

  • Royle, J. Forbes (John Forbes), 1798-1858.
Date:
1865
Catalogue details

Licence: Public Domain Mark

Credit: A manual of materia medica and therapeutics : including the preparations of the British pharmacopoeia, and many other approved medicines / by J. Forbes Royle and Frederick W. Headland. Source: Wellcome Collection.

    136/792 (page 124)
    several of the preparations of Ammonia, as the Liquor, Spirit, and Carb., or in obtaining C by the action of H CI on Marble. Prop. Chloride of Calcium (Ca CI = 55*5) is known in two forms. The first is the Anhydrous Chloride, which is hard, greyish- coloured, and semi-translucent. Being without water, it contains nearly twice as much Chlor. Calcium as the crystallised salt. It may be fused at a red heat, and becomes phosphorescent. It is very deliquescent, as is also the crystallised salt, passing readily into the liquid state, forming what used to be called Oleum Calcis. It is frequently employed to absorb moisture from gases, also to attract moisture to substances, with which it may be mixed, as the soil. It is very soluble in rectified spirit, also in water. When in solution its reactions are the same as if it were a Hydrochlorate of Lime, which indeed it may be. The second, or crystallised variety, contains 6 Eq. of Aq. (Ca CI -f 6 Aq.) It is colourless and without smell, of an acrid and bitter taste ; in striated hexagonal prisms terminated by very acute points. Water even at 32° dissolves more than its own weight, and at 60° above three or four times its weight of this salt. When heated, these crystals undergo watery fusion. Dissolved in water, they produce great cold; and hence are frequently employed as an ingredient in cold or freezing mixtures. The Chloride is used for concentrating Alcohol, which it does by its great affinity for water. This salt is in the Appendix of the B. P. The modes of preparing it are simple. Prep. White Marble or Chalk is dissolved in commercial H CI. The solution, when neutral, is concentrated and allowed to crystallise; more crystals are obtained by evaporation. The salt is then dried at a red heat, powdered when cold, and kept irom the air. The anhydrous Chloride is obtained in this way, and is intended by the B. P. The Carb. Lime (Oxide of Calcium) is decomposed, the C being expelled in the state of gas ; the Chlorine of the H CI combines with the Calcium, and forms Chloride of Calcium ; and the Hydrogen of the acid with the Oxygen of the Lime forms water. In the subse- quent part of the process the water of crystallisation is expelled. Tests. The presence of Calcium and of Chlorine will be revealed by their respective tests. Chloride of Calcium should be free from colour, slightly translucent, hard and friable, totally soluble in water: the solution gives no precipitate on the addition of Ammonia (showing the absence of Magnesia), or Lime, or Chlor. Barium (Sulphates), nor, when diluted with much water, with Ferrocyanide of Potassium (showing that it is not contaminated with Iron). This salt is very deliquescent. It should be entirely soluble in 2 parts of water. Action. Uses. Alterative. Dose. Gr. x.—xxx. A solution of one part in ten is used as a test, and the dry salt is employed in chemical processes as an absorbent of water. It is used in preparing Hydrochlorate of Morphia.