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Preparation of blue ink with Prussian blue
52
~lechanics, Physics, and Chemistry.
each being split and slightly turned out, so that when they have passed through the two sheets of copper they came in contact with the insulator, and are opened out--thus forming, as Captain Warren says, a perfect clench. The effect of the water wash at the part of the side avhere the copper leaves off, has also been provided against by Capt. Warren, who carries right round the vessel a batten or beam, on which the upper edge of the copper is fastened, but which is beveled in towards the ship's side at its downward edge, so as to twist the copper violently.
.Extracting the juice from Grapes. From the London Mechanics' Magazine, Oci;ober, 1864.
We learn from the Chemical .z]?'ewsthat a M. Richter, of Stuttgard, has devised'~ novel means of extracting the juice from grapes. Instead of pressing them in the ordinary way, he puts them in a drum provided with a suitable strainer, and rotating at the rate of 1000 or 1500 times a minute. The process is said to have the following advantages over the ordinary method :--The time required for the operation is greatly lessened, the whole of the must from one ewt. of grapes being obtained in five minutes; the quantity of juice is increased by five or six per cent.; "stalking" is rendered unnecessary; and the agitated must is so mixed with air that fermentation begins comparatively soon.
_Preparation of Blue Ink with _Prussian Blue. By M. A. Vo~Er~. From the London Chemical News, NO. 255.
Prussian blue dissolves in oxalic acid, giving a dark blue limpid liquid. This interesting discovery of MM. Stephen and Raseh, patented in England in 1837, is of great interest in tinetorial chemistry, as by its means Prussian blue may be very simply used in the form o f a solution. To dissolve commercial Prussian blue in oxalic acid, first mix the blue with concentrated hydrochloric or sulphurie acid, then add an equal weight of water, leave to digest for 48 hours, then carefully extract all the acid by repeated washings. This process being minute and tedious, it is better to employ recently precipitated Prussian blue, which does not need the previous treatment by a concentrated acid. By the following process the author has always obtained a good solid blue ink with Prussian blue and oxalic acid : Dissolve in a matrass, in a large quantity of water, ten grammes of sulphate of protoxide of iron; boil, and then add sufficient nitric acid to sesquioxidize all the iron. Then add a solution of yellow prussiate of potash containing ten grammes of this salt and leave the precipitate to deposit. After decanting the supernatant liquid, throw the deposit on a filter, wash with cold water, and leave itto drain until it can be easily raised from the filter with a knife; then, without further drying, mix it in a porcelian mortar with two grammes of oxalic acid in crystals. Let the reaction continue for an hour, then gradually add 400 cubic centimetres of water. A dark blue solution is thus obtained, in which even after long standing no precipitate is to be found.
~lechanics, Physics, and Chemistry.
each being split and slightly turned out, so that when they have passed through the two sheets of copper they came in contact with the insulator, and are opened out--thus forming, as Captain Warren says, a perfect clench. The effect of the water wash at the part of the side avhere the copper leaves off, has also been provided against by Capt. Warren, who carries right round the vessel a batten or beam, on which the upper edge of the copper is fastened, but which is beveled in towards the ship's side at its downward edge, so as to twist the copper violently.
.Extracting the juice from Grapes. From the London Mechanics' Magazine, Oci;ober, 1864.
We learn from the Chemical .z]?'ewsthat a M. Richter, of Stuttgard, has devised'~ novel means of extracting the juice from grapes. Instead of pressing them in the ordinary way, he puts them in a drum provided with a suitable strainer, and rotating at the rate of 1000 or 1500 times a minute. The process is said to have the following advantages over the ordinary method :--The time required for the operation is greatly lessened, the whole of the must from one ewt. of grapes being obtained in five minutes; the quantity of juice is increased by five or six per cent.; "stalking" is rendered unnecessary; and the agitated must is so mixed with air that fermentation begins comparatively soon.
_Preparation of Blue Ink with _Prussian Blue. By M. A. Vo~Er~. From the London Chemical News, NO. 255.
Prussian blue dissolves in oxalic acid, giving a dark blue limpid liquid. This interesting discovery of MM. Stephen and Raseh, patented in England in 1837, is of great interest in tinetorial chemistry, as by its means Prussian blue may be very simply used in the form o f a solution. To dissolve commercial Prussian blue in oxalic acid, first mix the blue with concentrated hydrochloric or sulphurie acid, then add an equal weight of water, leave to digest for 48 hours, then carefully extract all the acid by repeated washings. This process being minute and tedious, it is better to employ recently precipitated Prussian blue, which does not need the previous treatment by a concentrated acid. By the following process the author has always obtained a good solid blue ink with Prussian blue and oxalic acid : Dissolve in a matrass, in a large quantity of water, ten grammes of sulphate of protoxide of iron; boil, and then add sufficient nitric acid to sesquioxidize all the iron. Then add a solution of yellow prussiate of potash containing ten grammes of this salt and leave the precipitate to deposit. After decanting the supernatant liquid, throw the deposit on a filter, wash with cold water, and leave itto drain until it can be easily raised from the filter with a knife; then, without further drying, mix it in a porcelian mortar with two grammes of oxalic acid in crystals. Let the reaction continue for an hour, then gradually add 400 cubic centimetres of water. A dark blue solution is thus obtained, in which even after long standing no precipitate is to be found.