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Improved process for the evolution of boron
Itare on l/~e Evolution of.Boron.
291
ment is such that by a suitable movement in the sliding rod, made by grasping it by tile ban(lie G, in which it terminates externally, the cup may be made either to receive into its cavity the platina wire; or be made to adjust itself" to its covet" l-I.
The bell being remnved, l,o ts
ttoS
not containing more than fifteen ,,~'a'2'c3l bUemi'n't::o into the cup, which is then to be adjusted to the cover, and the bell secured. In the next place, by means of the flexible lead tubes, P, I', P, P, and tile galh)ws screws attached to tile valve cocks, establish a communication severally with an air pump, a selLregulating reset~voir of" hydr.ogen, a bm~o.meter gauge, and a jar over tile me,'curial mstern containing fluo-s~!lcm acid gas. First by means of the air pump exhaust the bell, and m order to wash out all remains of atmospheric air, admit hydrogen fi'om the reservoh-. Again exhaust anti again admit hydrogen. Lastly exhaust the bell of hydrogen and admit the fluo-silicic acid gas. By means of the gauge, the exhaustion is indicated and measured, anti by the same means it will be seen when the pressure of the gas within the bell approaches that of tile atmosphere. When this takes place, tile cocks being all closed, by means of a calorimotor, the platina wire is to be ignited, and the potassium brought into contact with it. A peculiar deep red combustion ensues, evolving copiously chocolate coloured fumes, which condensing into tlocks of t-he saint hue, subside throughout the receiver, like a snow in miniature, excepting tile colour. On removing the bell after the potassium is consumed, tile cup which held it, will be tbund to contain silicon mixed with the fluoride of potassium, and with this indeed the whole of the powder deposited is contaminated. Siliciuret of potassium is likewise formed in the cup, since on the afihsion of wafer, a fetid evolution ofsiliciuretted hydrogen ensues. By washing , the silicon, being insoluble, is left in the state of a chocolate coloured powder. According to Berzelius' directions, I have washed the silicon first with cold, and afterwards with boiling water, in order to purify it.
Improved proeess /br the evolution of Boron. By the author of the preceding, article. By means of an apparatus represented in the annexed engraving, I have succeeded in evolving boron by the reaction of potassium with vitrified boracic acid, in vacuo, without encountering the evil of any explosive action, to which the process, as heretofore conducted, in pleno, has been found liable. A circular brass plate, is prepared, like the plate of an air pump, so as to produce with any suitable receivers properly ground, an air-tight juncture. It is supported on the upper end of a hollow brass cylinder, B, with the bore of whictl it has a corresponding aperture. The brass cylinder is about three inches in diameter, and six inches in height, being inserted at its lower end into a block of
292
tla~'e on the Evolution o f Boron.
wood as a basis. Tiffs cylinder receives below, a screw, which supports a copper tube, C, of about two inches in diameter, so as to have its axis concentric with that of the cylinder, and to extend about four inches above the plate. The copper tube, thus supported~is
closed at the upper termination by a cup of copper, of a shape nearly hemispherical, and soldered at the upper edge, to the edge of the tube; so that the whole of the cavity of the cup, is within that of the tube.
Hare's New Valve Cock.
293
Hence the bottom of tlle cup is accessible to any body, not larger than the bore of the tube, without any communication arising between the cavity of the tube, and that of any receiver placed upon theplate, over tile cup and tube, as in the figure. Into the side of the cylinder supporting the plate, a valve cock is screwed, by means of which, anti a flexible leaden tube, a communication with an air-pump is opened, or discontinued, at pleasure. The cup being first covered with a portion of tile vitrified boracic acid, as anhydrous as possible, and finely pulverized, the potassium is introduced, and afterwards covered with a further portion of the same acid, two parts of tile potassium being used for one of the acid. A large glass receiver is now to be placed on the plate, secured by rods A, A, concentric with the tube and cup; from the heat of which the glass is to be protected by a bright cylinder of sheet brass, S, placed around it so as to be concentrical with the receiver and tube. The apparatus being so far prepared, an incandescent iron is introduced through the bore of the tube, so as to touch the bottom of the copper cup. In a short time a reaction commences, which aiding the influence of the hot iron, renders tile cup and its contents red hot. A deep red flame appears throughout the mass, after which the reaction lessens, and the heat declines. When the cup has become cold, the air is admitted into the receiver, and tile contents are washed with water. It" any of the acid has escaped decomposition, it may be removed by boilihg tile mass with a solution of potash or soda. After this treatment and due desiccation, a powder will remain, having the characteristic colour and properties of boron. The additional valve cock, represented in the figure, gives the option of introducing dry hydrogen for the purpose or washing out atmospheric air, as described in the process for silicon.
Description of the Valve Cock, a perfectly air.tight substitute for the common Cock. B y the author of the preceding articles, in which it is referred to. This figure is intended to illustrate the construction of a substitute for a common cock which I have been accustomed to call a valve cock. It was devised by me about twenty years ago, among a number of other analogous contrivances, and seems upon the whole less liable to fail than any other which I have tried. The engraving rel,resents a longitudinal section of the valve cock. At a is a piston with a collar enclosed in the stuffing box b, so as to be rendered airtight by means of oiled leather. Hence this piston may be turned or made to revolve on its axis, while incapable of other motion. Upon the end of the piston a thread for a screw is cut which fits into a female screw in the brass prism c, so as to cause this prism to approach to or to retreat from a bearing covered by leather, in the centre of" which there is a perforation o o communicating with one of the orifices of the instrument. This orifice is surrounded by the male screw el, so that
291
ment is such that by a suitable movement in the sliding rod, made by grasping it by tile ban(lie G, in which it terminates externally, the cup may be made either to receive into its cavity the platina wire; or be made to adjust itself" to its covet" l-I.
The bell being remnved, l,o ts
ttoS
not containing more than fifteen ,,~'a'2'c3l bUemi'n't::o into the cup, which is then to be adjusted to the cover, and the bell secured. In the next place, by means of the flexible lead tubes, P, I', P, P, and tile galh)ws screws attached to tile valve cocks, establish a communication severally with an air pump, a selLregulating reset~voir of" hydr.ogen, a bm~o.meter gauge, and a jar over tile me,'curial mstern containing fluo-s~!lcm acid gas. First by means of the air pump exhaust the bell, and m order to wash out all remains of atmospheric air, admit hydrogen fi'om the reservoh-. Again exhaust anti again admit hydrogen. Lastly exhaust the bell of hydrogen and admit the fluo-silicic acid gas. By means of the gauge, the exhaustion is indicated and measured, anti by the same means it will be seen when the pressure of the gas within the bell approaches that of tile atmosphere. When this takes place, tile cocks being all closed, by means of a calorimotor, the platina wire is to be ignited, and the potassium brought into contact with it. A peculiar deep red combustion ensues, evolving copiously chocolate coloured fumes, which condensing into tlocks of t-he saint hue, subside throughout the receiver, like a snow in miniature, excepting tile colour. On removing the bell after the potassium is consumed, tile cup which held it, will be tbund to contain silicon mixed with the fluoride of potassium, and with this indeed the whole of the powder deposited is contaminated. Siliciuret of potassium is likewise formed in the cup, since on the afihsion of wafer, a fetid evolution ofsiliciuretted hydrogen ensues. By washing , the silicon, being insoluble, is left in the state of a chocolate coloured powder. According to Berzelius' directions, I have washed the silicon first with cold, and afterwards with boiling water, in order to purify it.
Improved proeess /br the evolution of Boron. By the author of the preceding, article. By means of an apparatus represented in the annexed engraving, I have succeeded in evolving boron by the reaction of potassium with vitrified boracic acid, in vacuo, without encountering the evil of any explosive action, to which the process, as heretofore conducted, in pleno, has been found liable. A circular brass plate, is prepared, like the plate of an air pump, so as to produce with any suitable receivers properly ground, an air-tight juncture. It is supported on the upper end of a hollow brass cylinder, B, with the bore of whictl it has a corresponding aperture. The brass cylinder is about three inches in diameter, and six inches in height, being inserted at its lower end into a block of
292
tla~'e on the Evolution o f Boron.
wood as a basis. Tiffs cylinder receives below, a screw, which supports a copper tube, C, of about two inches in diameter, so as to have its axis concentric with that of the cylinder, and to extend about four inches above the plate. The copper tube, thus supported~is
closed at the upper termination by a cup of copper, of a shape nearly hemispherical, and soldered at the upper edge, to the edge of the tube; so that the whole of the cavity of the cup, is within that of the tube.
Hare's New Valve Cock.
293
Hence the bottom of tlle cup is accessible to any body, not larger than the bore of the tube, without any communication arising between the cavity of the tube, and that of any receiver placed upon theplate, over tile cup and tube, as in the figure. Into the side of the cylinder supporting the plate, a valve cock is screwed, by means of which, anti a flexible leaden tube, a communication with an air-pump is opened, or discontinued, at pleasure. The cup being first covered with a portion of tile vitrified boracic acid, as anhydrous as possible, and finely pulverized, the potassium is introduced, and afterwards covered with a further portion of the same acid, two parts of tile potassium being used for one of the acid. A large glass receiver is now to be placed on the plate, secured by rods A, A, concentric with the tube and cup; from the heat of which the glass is to be protected by a bright cylinder of sheet brass, S, placed around it so as to be concentrical with the receiver and tube. The apparatus being so far prepared, an incandescent iron is introduced through the bore of the tube, so as to touch the bottom of the copper cup. In a short time a reaction commences, which aiding the influence of the hot iron, renders tile cup and its contents red hot. A deep red flame appears throughout the mass, after which the reaction lessens, and the heat declines. When the cup has become cold, the air is admitted into the receiver, and tile contents are washed with water. It" any of the acid has escaped decomposition, it may be removed by boilihg tile mass with a solution of potash or soda. After this treatment and due desiccation, a powder will remain, having the characteristic colour and properties of boron. The additional valve cock, represented in the figure, gives the option of introducing dry hydrogen for the purpose or washing out atmospheric air, as described in the process for silicon.
Description of the Valve Cock, a perfectly air.tight substitute for the common Cock. B y the author of the preceding articles, in which it is referred to. This figure is intended to illustrate the construction of a substitute for a common cock which I have been accustomed to call a valve cock. It was devised by me about twenty years ago, among a number of other analogous contrivances, and seems upon the whole less liable to fail than any other which I have tried. The engraving rel,resents a longitudinal section of the valve cock. At a is a piston with a collar enclosed in the stuffing box b, so as to be rendered airtight by means of oiled leather. Hence this piston may be turned or made to revolve on its axis, while incapable of other motion. Upon the end of the piston a thread for a screw is cut which fits into a female screw in the brass prism c, so as to cause this prism to approach to or to retreat from a bearing covered by leather, in the centre of" which there is a perforation o o communicating with one of the orifices of the instrument. This orifice is surrounded by the male screw el, so that