The London manual of medical chemistry, comprising an interlinear verbal translation of the Pharmacopoeia, with extensive ... notes ... together with the treatment and tests of poisons, and ... the theory of pharmaceutical chemistry ... / By William Maugham.

  • Maugham, William.
Date:
1831
Catalogue details

Licence: Public Domain Mark

Credit: The London manual of medical chemistry, comprising an interlinear verbal translation of the Pharmacopoeia, with extensive ... notes ... together with the treatment and tests of poisons, and ... the theory of pharmaceutical chemistry ... / By William Maugham. Source: Wellcome Collection.

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    consider this part of the subject through all its bearings, I as crystallography of itself forms a distinct science. I To enable a body to crystallize, it must be brought | into a liquid or aeriform state; thus, if we dissolve cer- j tain substances in water, and then get rid of a portion of ; the water by evaporating the solution, we obtain crys- i tals more or less regular in their structure; some of the metals crystallize in cooling from the state of fusion; and benzoic acid and other bodies condense in a crystalline state in cooling as in the process of subli- ] mation. In the case of solution, if the evaporation be conducted rapidly by the aid of heat, a confused crys- talline mass will be the result; but if the evaporation take place slowly, regular crystals will be formed ; the slower the evaporation, the more regular will be the crystals; so that the most perfect crystals are obtained by spontaneous evaporation. Some bodies during the act of crystallizing from a state of solution, carry down with them a portion of i water, which is called water of crystallization ; this dif- fers in quantity in the crystals of different bodies, but it is always the same in the crystals of the same body, and is therefore chemically combined. When crystals of this kind are exposed to heat, they undergo what is called watery fusion^ the crystallized body, if soluble, becoming dissolved in its own water of crystallization. Such crystals are entirely deprived of their water by exposing them to a red heat. The crystals of some bodies are devoid of water of crystallization; but they may nevertheless contain water.