Specification of Pierre Alexis Francisse Bobœuf : preserving and otherwise treating animal and vegetable substances, &c.

  • Bobœuf, Pierre Alexis Francisse.
Date:
1858
Catalogue details

Licence: Public Domain Mark

Credit: Specification of Pierre Alexis Francisse Bobœuf : preserving and otherwise treating animal and vegetable substances, &c. Source: Wellcome Collection.

    16/18 (page 14)
    JBoboeufs Impts. in Preserving, eye. Animal and Vegetable Substances, c^c. from their various solutions are brown and red. When it is desired to stain animal substances, or substances of animal origin, it is necessary to dissolve the coloring matter of the derived acids (which, for abbreviation, I shall call tri-nitro-phenic acids) in warm water, in the proportion of one part of acid to 1000 parts of warm water; boil the whole for 10 minutes, and then let 5 it stand, in order that oils which may be lodged amongst the crystals may settle to the bottom ; filter and then decant. Boil the solution, and plunge into it the objects to be colored, and afterwards rinse them in pure water. When the tri-nitro-phdnic acid combined with alum in the manner herein-before described is employed, then 5 parts of acid must be added to the 1000 parts 10 of water. This combination of tri-nitro-phenic acid and alum has the following important advantages as a coloring agent over the acid alone:—1st, it can be used immediately after its dissolution without injury to the substances operated on, which is not the case with ordinary tri-nitro-phenic acid ; 2nd, because the alum combines with nearly all tissues, and its combination produces purer 15 and more lasting colors; 3rd, it is much more easily and comfortably mani¬ pulated, and much more cleanly. This application of the yellow solutions of tri-nitro-phenic acid is not entirely newr, and I do not claim it as my Invention, for this substance has been for several years employed as a coloring agent. I claim, however, the mode of preparing this coloring matter which I have 20 described, a method which is greatly superior to those hitherto known ; and the coloring matter, as already stated, possesses the great advantage of being applicable immediately after it is dissolved without injury to the animal substances colored. When the acid derived by substitution is but little or not at all soluble 25 in w’ater, it must then be treated with some caustic alkali to form a salt soluble in water, and which in these circumstances ordinarily gives solutions of a yellowish browm color. These solutions are very good coloring agents. It is necessary in all cases to take care to rinse the substances operated on in W’ater slightly acidulated, in order to fix the color. With reference to the red 30 coloring matter which may also be obtained, I have not yet succeeded in producing it economically enough to speak further of it at present. The mode of preparing tri-nitro-phenic acid, as heretofore conducted, consists in taking ordinary oil of coal, or the same oil distilled, and treating it with eight times its weight of nitric acid ; but from this process is obtained 35 merely a viscous mass containing at most not more than 33 per cent, of real tri-nitro-plienic acid, while the process I have described gives a result con¬ taining nearly 90 per cent, of the acid. With regard to these properties but one particular fact has hitherto been discovered and pointed out, viz., that the