Part 76

«Wool, Silk, or Straw.»—Mix together 4 pounds of oxalic acid, 4 pounds of table salt, water 50 gallons. The goods are laid in this mixture for 1 hour; they are then generally well bleached, and only require to be thoroughly rinsed and worked. For bleaching straw it is best to soak the goods in caustic soda, and afterwards to make use of chloride of lime or Javelle water. The excess of {121} chlorine is afterwards removed by hyposulphite of soda.

«Feathers.»—Place the feathers from 3 to 4 hours in a tepid dilute solution of bichromate of potassa, to which, cautiously, some nitric acid has been added (a small quantity only). To remove a greenish hue induced by this solution, place them in a dilute solution of sulphuric acid, in water, whereby the feathers become perfectly white and bleached.

«Bleaching Solution.»—Aluminum hypochloride, or Wilson’s bleaching liquid, is produced by adding to a clear solution of lime chloride a solution of aluminum sulphate (alumina, alum) as long as a precipitate keeps forming. By mutual decomposition aluminum chloride results, which remains in solution, and lime sulphate (gypsum), which separates out in the form of an insoluble salt.

«BLIGHT REMEDIES.»

I.—Soft soap 40 parts Amyl alcohol 50 parts Methylated spirit 20 parts Water 1,000 parts II.—Soft soap 30 parts Sulphureted potash 2 parts Amyl alcohol 32 parts Water 1,000 parts III.—Soft soap 15 parts Sulphureted potash 29 parts Water 1,000 parts

BLEACHING SOLUTIONS FOR THE LAUNDRY: See Laundry Preparations.

BLEACHING SOLUTION FOR PHOTOGRAPHS: See Photography.

BLEEDING, LOCAL: See Styptics.

BLISTER CURE: See Turpentine.

BLISTERS, FOR HORSES: See Veterinary Formulas.

BLOCK, HOLLOW CONCRETE BUILDING: See Stone, Artificial.

BLOCK FOR SOLDERING: See Soldering.

BLOTTING PAPER: See Paper.

«BLUE FROM GREEN AT NIGHT, TO DISTINGUISH:»

To distinguish blue from green at night, use either the light of a magnesium wire for this purpose or take a number of Swedish (parlor) matches, light them, and as soon as they flash up, observe the 2 colors, when the difference can be easily told.

BLUE (BALL): See Dyes.

BLUING: See Laundry Preparations.

BLUING OF STEEL: See Steel.

«BLUE PRINTS, TO MAKE CHANGES AND CORRECTIONS ON:»

Use a solution of sodium carbonate and water, with a little red ink mixed in. This gives a very pleasing pink color to the changes which, at the same time, is very noticeable. The amount of sodium carbonate used depends upon the surface of the blue-print paper, as some coarse-grained papers will look better if less soda is used and vice versa. However, the amount of powdered soda held on a small coin dissolved in a bottle of water gives good results.

BLUE-PRINT PAPER MAKING: See Photography.

BLUE PRINTS, TO TURN BROWN: See Photography, under Toning.

«BOIL REMEDY.»

Take a piece of soft linen or borated gauze, rub some vaseline upon one side of it, quickly pour upon it some chloroform, apply it to the unopened boil or carbuncle, and place a bandage over all. It smarts a little at first, but this is soon succeeded by a pleasing, cool sensation. The patient is given a bottle of the remedy, and directed to change the cloth often. In from 2 hours to 1 day the boil (no matter how indurated) softens and opens.

«Boiler Compounds»

There are three chemicals which are known to attack boiler scale. These are caustic soda, soda ash, and tannic-acid compounds, the last being derived from sumac, catechu, and the exhausted bark liquor from tanneries.

Caustic soda in large excess is injurious to boiler fittings, gaskets, valves, {122} etc. That it is injurious, in reasonable excess, to the boiler tubes themselves is yet to be proved. Foaming and priming may be caused through excess of caustic soda or soda ash, as is well known by every practical engineer. Tannic acid is to be condemned and the use of its salts is not to be recommended. It may unite with the organic matter, present in the form of albuminoids, and with calcium and magnesium carbonates. That it removes scale is an assured fact; that it removes iron with the scale is also assured, as tannic acid corrodes an iron surface rapidly.

Compounds of vegetable origin are widely advertised, but they often contain dextrine and gum, both of which are dangerous, as they coat the tubes with a compact scale, not permitting the water to reach the iron. Molasses is acid and should not be used in the boiler. Starch substances generally should be avoided. Kerosene must be dangerous, as it is very volatile and must soon leave the boiler and pass over and through the engine.