Historical introduction to chemistry / by T.M. Lowry.

  • Martin Lowry
Date:
1915
Catalogue details

Licence: In copyright

Credit: Historical introduction to chemistry / by T.M. Lowry. Source: Wellcome Collection.

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    the chalk was usually dissolved, but oil of vitriol gave a white solid which was proved by Margraaf, in 1750, to be identical with the mineral gypsum or selenite (Fig. 10, p. 19), from which “Plaster of Paris” is made by gentle burning. The origin and the nature of the “air” which is set free in these actions are discussed in Chapters IV. and VI. Action of acids on metals.—The acids also had the property of corroding or dissolving metals. The poisonous green powder known as verdigris was prepared at a very early date by the action of vinegar on copper, and was used as a paint during the classical period. The mineral acids were found to act on metals in a much more powerful way; by the time of Geber (circ. 800 a.d.) methods had been discovered for dissolving all the metals that were known. The action of acids on metals was often accompanied (as in the case of soda and chalk) by the breaking out of a gas, but for many centuries no method was known by which these fugitive products could be collected. The important discoveries which were made when at last it was found possible to isolate and examine them are described in Chapter V. C. Preparation of New Salts and Nomenclature of Salts New salts.—One result of the discovery of the acids was to add very greatly to the number of “salts” which were known. When an acid acts on a metal, on chalk, or on an alkali, a solution is produced which no longer has the sour taste of the acid. These solutions contain a variety of salt-like substances, which can be isolated by evaporating either to dryness or until crystals begin to separate. In this way many beautiful and useful salts were obtained. At first a special name was given to each salt ; but later a
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