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To Bleach Lac

Dissolve the Feathers. This process is an entirely newprocess is an entirely newlac in a boiling lye of pearlash or caustic pot-ly-discovered one, whereby the feathers of ash, filter it and pass chlorine through the ostriches and other birds may be bleached, solution until all the lac is precipitated. Col- even if these feathers are naturally black or dark gray colored. The feathers are placed is precipitated. Col- even if these feathers are naturally black or lect the precipitate, wash well in hot water, dark gray colored. The feathers are placed and finally twist into sticks, and throw them for from 3 to 4 hours in a tepid dilute solution air. of bichromate of potassa, to which, cautiously, and mix. Stir in 7 pounds hydrate of lime in some nitric acid has been added. After this very fine powder. The thick mass is now lapse of time the feathers will be found to roasted, stirring all the time till it is reduced have assumed a greenish hue, owing to the to a fine powder. It is then ignited in a oxide of chromium precipitated on the sub-covered crucible till all the vegetable matter stance; in order to remove this, the feathers is carbonized. The charcoal, when cold, is are placed in a dilute solution of sulphurous digested with dilute hydrochloric acid, and acid in water, whereby the feathers become finally washed with water in a filter, and perfectly white and bleached. Care is to be dried. Dr. Stenhouse recommends this as an taken that the solution of bichromate be not admirable form for decolorization. For such made too strong, and especially that not too liquids as decoction of logwood it is four times much nitric acid be used, which would cause an irremovable yellow color. as efficient as animal charcoal.

Vinegar.or Vinegar is dilute acetic 1728. Table Showing the Number of Parts of a Weak Bleaching Liquor, Required to be added to 1 Part Bleaching Liquor of 6° Twaddell, to Produce a Liquor of a given Strength. According acid less mixed with gum, to Mr. Crum, the strength of liquor for bleach- sugar, and other vegetable matter. It can be ing cotton should be less than 10 Twaddell; made from any liquid which is susceptible of the following table enables an operator to in- the vinous fermentation. In this country it crease the strength of a weak bleaching liquor is made chiefly from cider and alcoholic liwith a great degree of accuracy. The left quors; in England, from malt liquors and hand column gives the strength of the weak molasses; in wine growing countries, from liquor, expressed in T½ parts of 10. At the inferior or damaged wine. The cultivation of head of the other columns stands the degree the vine is gradually gaining importance in of strength required, and under these headings will be found the number of parts of weak liquor required to be added to 1 part of a liquor of 6º Twaddell, to produce the required strength of the mixture. (See No. 68.) Strength of Sample.

Water.

Strength Required. 82° 。 8 parts 11 parts 17 parts 23 parts 9" 13+ " 23 “ 10 12 11 “ 17 3 12 13 " 23 “ 35 71 12 17 “ 35 12 23 “ 71 “ B 35 66 71 “ “ “ “ “ 35 71 “ 65