The pharmacopoeia of the Royal College of Physicians of London, MDCCCIX / Translated into English with notes, &c. by Richard Powell.

  • Royal College of Physicians of London.
Date:
1809
Catalogue details

Licence: Public Domain Mark

Credit: The pharmacopoeia of the Royal College of Physicians of London, MDCCCIX / Translated into English with notes, &c. by Richard Powell. Source: Wellcome Collection.

    64/512 (page 12)
    The Sand Bath may have its heat raised to redness, and it is oftcn required to be so, but the gradual transmission of heat through this medium prevents that destruction of glass vessels which more sudden changes of temperature are apt to occasion, and it is also more manageable in itself; hence it has great advantages in the majority of processes over a naked fire. The following explanation of some other operations em- ployed in pharmacy may not be useless. Filtration is a mode of separating from liquids those solid substances which differ but little in their specific gravity, and subside but slowly. For the nicer purposes of Pharmacy, bibulous paper must be used folded into a conical form and placed within a funnel; it should be colourless, which may be easily obtained,and therefore not theblottingpaper ofordinary use. For other preparations, linen, woollen, or cotton cloths may be employed, which allow the liquid to pass readily through them, and which, therefore, are especially applicable to Solutions of vegetable matters, and separation of them from their insoluble parts when required for immediate use. The stronger acids which would destroy filtres made of animal or vegetable matter, if thev require filtration, must be passed through pounded glass, retained in the funnel bv a few larger pieces first introduced into its neck. For the separation of supernatant liquids from substances of great specific gravity, and which readily subside to the bottom, Dccantation is used; which means, that the fluid shall be carefully poured off without disturbing the hcavier substance which has subsided to the bottom. Evaporation is used for separating water or any other vola- tile fluid from those which are fixed in the same degree of heat. It is therefore performed by the application of heat, and it is promoted by using shallow vessels, and extending