A family herbal: or, Familiar account of the medical properties of British and foreign plants, also their uses in dying, and the various arts, arranged according to the Linnaean system / [Robert John Thornton].

  • Thornton, Robert John, 1768?-1837.
Date:
1814
Catalogue details

Licence: Public Domain Mark

Credit: A family herbal: or, Familiar account of the medical properties of British and foreign plants, also their uses in dying, and the various arts, arranged according to the Linnaean system / [Robert John Thornton]. Source: Wellcome Collection.

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    and put into a still with a proportion of water. After the water has been kept boiling forty-eight hours, the camphor is found adhering to the straw with which the head of the still is lined. In this state it is imported by the Dutch, and is called crude camphor. It is very impure, consisting of small brownish or dirty-gray grains, mixed with straw, wood, hair, and other impurities. From these it is purified in Holland by a second sublimation in glass vessels; being previously mixed with quick¬ lime, to combine with and prevent any empyreumatic oil with which it may be contaminated from subliming, while the cam¬ phor concretes in the upper part of the vessel into cakes, convex on the one side and concave on the other, about twro or three inches thick, thinner at the edges, and generally perforated in the middle. Pure camphor is lighter than water, very white, pellucid, somewhat unctuous to the touch, brittle, yet tough and clastic, so as to be scarcely pulverizable; shining in its fracture, and crystalline in its texture; of a bitterish, aromatic, pungent taste, yet accompanied with a sense of coolness, of a strong and very penetrating smell; very volatile, inflammable, burning entirely away, without leaving any coal or ashes : capable of combining with the resins and balsams ; soluble in alcohol, aether, fixed and volatile oils, and the concentrated sulphuric, nitric, muriatic, fluoric, and acetic acids ; separable from these alcoholic and acid solutions by water; insoluble in water, alkalis, and the weaker acids; decomposed by heat, when mixed with alumina, into an essential oil and charcoal; and by treating it with a sufficient quantity of nitric acid, forming a portion of camphoric acid ; and by treating it with sulphuric acid, forming artificial tannin. But the production of camphor is not confined to the Laurus camphora, although it furnishes almost all the camphor of com¬ merce; it is found in very great purity in interstices among the woody fibres of an unknown tree in Borneo ; it is also con¬ tained in the roots of the Laurus cinnamomum and cassia, Alpinia galanga, Amomum zedoaria, Ac.; in the seeds of the Amomum cardamomum, Piper cubeba, Ac.; and in many indigenous plants, as in the Thymus serpyllum and vulgaris, Juniperus communis, Rosmarinus officinalis, Salvia officinalis, Mentha piperata, Ac.; and may be separated from the essential oils of rosemary, lavcn- dar, marjoram, and sage. An artificial camphor may also be prepared, by directing a stream of muriatic acid gas into oil of