Volume 2
Institutes of experimental chemistry : being an essay towards reducing that branch of natural philosophy to a regular system ... / By the author of the Elaboratory laid open [i.e. Robert Dossie].
- Dossie, Robert, -1777
- Date:
- 1759
Licence: Public Domain Mark
Credit: Institutes of experimental chemistry : being an essay towards reducing that branch of natural philosophy to a regular system ... / By the author of the Elaboratory laid open [i.e. Robert Dossie]. Source: Wellcome Collection.
100/476 page 90
![in fuch quantities, as to anfwer any commer= cial end. | id The method of extracting gums, by com- preffure, is feldom practifed here, but on the poppies: and there the gum, which is ex- tracted, is not reduced to a dry body, but kept in a diffolved ftate, in the form of a fyrup; fugar being added to the folution for that end. The method of extraction, by coétion, is more frequently ufed, both in the formation of mucilages, for medicinal ufes, and in the preparation of pigments and tinctures, for the purpofes of painting and dying: particularly with refpect to the latter, from the feeds called the French berries, weld, and other fuch ve- getable fubftances, as yield their tinging matter to water. ; EXPERIMENT I]. Solution of gums in water. Powder the gums; and add. them gra- dually to a due proportion of water, which, for the readier » difpatch, fhould be of a boiling heat, ftirring the mixture well about, or fhaking the veffel which contains it, till the powder appear to be diffolved. . | _ In the more perfect gums, a tranfparent equal folution is obtained: but in others, as the Ammoniacum, a laéteous, or milky folution is the refult. In the ‘gum-traga- 8 | canth,](https://iiif.wellcomecollection.org/image/b30530209_0002_0100.jp2/full/800%2C/0/default.jpg)
