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Sulphuration

The process by BLEACHING. &c., are bleached or decolored by exposure to into cold water to harden. Lac thus purified the fumes of burning sulphur. This is effected is used to make pale varnishes and the more delicate tints of colored sealing-wax. Shelsulphur. This is effected is used to make pale varnishes and the more in a close chamber of a size proportioned to the delicate tints of colored sealing-wax. Shel- The following scale on which the operation is conducted, lac bleached by this method is liable to stain furniture inlaid with brass. The following operation is conducted, lac bleached by this method is liable to stain and supplied with only just sufficient air to furniture inlaid with brass. keep up the slow combustion of the sulphur, process is free from this objection, and has the additional advantage of being much of the sulphur, process is free from this objection, and has the fumes of which are sulphurous acid. cheaper: are sulphurous acid. the additional advantage of being much (See Nos. 360 and 364.) cheaper:

1718. To Prepare Sulphurous Acid 1724. Το Bleach Shellac with Anifor Bleaching. Sulphurous acid is used mai Charcoal Any quantity of yellow sheleither as gas or in solution in water, which lac, previously broken in small pieces, is conin water, which lac, previously broken in small pieces, is condissolves 50 times its volume of the gas. In veyed into a flask, alcohol of 830 specific gravits volume of the gas. In veyed into a flask, alcohol of,830 specific gravthe former case sulphur is burned in a close ity poured upon it, and the whole heated on a stove, or, in the summer, in the sun, until burned in a close ity poured upon it, and the whole heated on room in which the stuffs (moistened) are the shellac is dissolved; upon this so much (moistened) are a stove, or, in the summer, in the sun, until hung; for small articles a barrel with a lid the shellac is dissolved; upon this so much answers well. 2 exposures, of 24 hours cach, coarsely powdered animal charcoal is added to the solution that the whole forms a thin , of 24 hours cach, coarsely powdered animal charcoal is added suffice for wool. (See No. 300.) To get a to the solution that the whole forms a thin solution of sulphurous acid, the cheapest and paste; the flask is closed, not quite air-tight, best plan is to heat in a glass retort 12 ounces and left so for some time exposed to the sun; and in 8 to 14 days a small sample is filtered, glass retort 12 ounces and left so for some time exposed to the sun; sulphuric acid and 2 ounces sulphur. The gas, which comes off quietly, is collected in a large glass bottle partially filled with water; or, better, a series of bottles SO connected bottles so connected together that the gas must pass successively through the water contained in each. in each.

1719. A New Wash for Wool and Silk. Instead of using the fumes of sulthe fumes of sulphur, M. Frezon proposes the following mixand in 8 to 14 days a small sample is filtered, sufficient to ascertain whether it has acit has acquired a light yellowish brown color, and whether it yields a clear, pure polish, on light colored woods. If this be the case, it is filbe the case, it is filtered through coarse blotting paper, for which purpose it is best to employ a tin funnel with double sides, similar to those employed in filtering spirituous solutions of soaps, opodelof soaps, opodelture: 4 pounds oxalic acid, 4 pounds table doc, &c. The portion which first passes salt, 200 quarts water. The goods are laid in through the filter may be preserved separate- ly, and used as a ground or first polish. The goods are laid in through the filter may be preserved separatethis mixture for an hour. They are then gen- They are then gen-ly, and used as a ground or first polish. erally well bleached, and only require to be Then some more spirit is poured over the thoroughly rinsed and washed. For bleach- charcoal upon the filter, and the solution used as a last coating. The solution of shelwashed. For bleach- charcoal upon the filter, and the solution ing straw it is best to soak the goods in caus- used as a last coating.

The solution of sheltic soda and afterwards to make use of chlor- lac purified by animal charcoal has a brown ide of lime or Javelle water. (Sce Index.) yellow color, but it is perfectly clear and The excess of chlorine is afterwards to be re- transparent; when diluted with alcohol, the moved by hyposulphite of soda, called anti- color is SO slight that it may be used in this state for polishing perfectly white wood, such soda, called anti-color is so slight that it may be used in this chlor.