Vitriol color

The last-named authority has remarked with reference to British gum prepared by sulphuric acid, that it possesses the disadvantageous property of being deliquescent. This method is, therefore, never employed, as besides this, the products are often colored. He also states that when nitric arid is employed in the preparation of dextrin, it must be perfectly pwe. Commercial nitrio acid, as obtained by the action of oil of vitriol upon nitrats of Soda, always contains a small amount of chlorine and although this element is contained in diminished proportion in the dextrin, it is nevertheless sufficient to considerably lessen the brilliancy of the colors prepared with the dextrin. Several printers upon paper and vegetal tissues have observed this, but have been unable to account for it otherwise than by attributing it to the iaferior quality of the gum. 

Sesquioxide of Iron—Fe 0.—This is prepared by the calcination of green vitriol, upon the purity of which the brilliancy of the color in a great measure depends, For the calcination a thick cast-iron vessel or earthenware retort is required. During the operation the 5... 

Oxides of Copper—red oxide of copper—Cu, 0—is prepared by heating one hundred parts of blue vitriol with fifty-seven parts of carbonate of soda until the water of crystallization Is expelled. The rosiduum is afterwards mixed with twenty-five parts of copper filings, and the mixture finely stamped into a crucible. It iB then exposed to a white boat for about twenty minutes, and after cooling and pulverization, the mass is well washed with water. ThiB process yields about fifty parts of fine colored red oxide of copper. 

The value of chalcanthum in coloring leather black, doubtless in conjunction with tannin, would depend upon the iron present, and as both Dioscorides and Pliny refer to variations in color of different grades of chalcanthum, it is evident that both green and blue vitriol and mixtures of the two passed under that designation. 

The separation of the elements from metals is a process in which you should provide yourself with good apparatus, and with experienced manipulation and workmanship. First make an aqua fortis thus take of alum, vitriol, sal-nitri, equal parts, distil to a strong aqua fortis, return that to the residue and distil a second time in a glass flask. Dissolve in this silver and afterwards dissolve in it sal ammoniac. After this is done take the metal in thin plates and dissolve it in the water. When that has taken place separate it in the water bath (balneo mar is), pour it over again until an oil is found at the bottom from gold almost brown, from silver almost bluish, from iron red to almost black, from mercury quite white, from lead lead-colored, from copper quite green, from tin, yellow. 

Lab grade hematite (Fe203) and copper sulfate (anhydrous and hydrated) were mounted on slides and used as controls to compare to mineral deposits that might have been found adhering to foe fibers. Rabbit hair and milkweed that had been colored with an aqueous hematite solution and with an aqueous copper sulfate (blue vitriol) solution were also used for comparison. Fibers removed from each simulated material were mounted in water (Refractive Index (Rl) of 1.0), and in Permount (Fisher Scientific) (RI of 1.55). The collected particulate matter and fibers removed from foe yam samples were similarly mounted and examined using optical microscopy. 

A second example illustrates the ability of transition metals to form complexes with small molecules and ions. Copper metal and hot concentrated sulfuric acid ( oil of vitriol ) react to form solid copper(II) sulfate, commonly called blue vitriol by virtue of its deep blue color. There is more to this compound than copper and sulfate, however it contains water as well. When the water is driven away by heating, the blue color vanishes, leaving greenish white anhydrous copper(II) sulfate (Fig. 8.11). The blue color of blue vitriol comes from a... 

The crystalline hydrates are generally speaking vitriols of the composition M(II)S04 7 H2O. Like the stable manganese vitriol, copper vitriol crystallises with 5 molecules of water of crystallisation per metal ion. Mixed colors can appear if ammonium metavanadate is used as the starting material in test tube 1 because of the presence of several oxidation states of vanadium. 

To Decolorize Kavosene Oil. Kerosene oil is decolorized b stirring it uj> with 1 or 2 per cent, of oil ol vitriol, which will carbonize tho coloring matter, then with some milk of Umo or some other caustic alkali, settling, aud redistilling. Tho latter appears to be indispensable. 

Gallic Acid. When pure. gaUic acid forms small, feathery, and nearly color-loss crystals, which have a beautiful silky lustre. Commercial gallic acid has usually a pale yellow color, soluble in both water and alcohol. Its aqueous solution decomposes by exposure to the air. It blackens the salts of iron. Dissolved in hot oil of vitriol, it forms a deep, rich, red solution, which, when thrown into water, drops the gallic acid, deprived of some of its water. Gallic acid forms qaIt LATEs with the bases. 

To Test Tea. Pure China tea is not turned black by being put into water impregnated with sulphuretted hydrogen gas, nor does it tinge spirit of hartshorn blue. The infusion is amber-colored, and is not reddened by adding a few drops of oil of vitriol to it. 

Zb Bemove Blue Color firm (Sfest—Inamersefor a few minutes in a liquid composed of equal parte muriatic add and oil of vitrioL Rtnae in pure waterand rub dry with chamois akin or some kind of eoft doth. 

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