2480. Blue Writing Fluid

2480.    Blue Writing Fluid. Dissolve the soluble ferrocyanide of potassium and iron in pure water. Eesembles No. 2478, but is precipitated from its solution by alcohol.

2481. Stephens' Patent Blue Ink

2481. Stephens' Patent Blue Ink. Mr. Stephens' process. Take Prussian blue, (cither of commerce, or the pure chemical combination of sesquioxide of iron with ferrocyanide of potassium), put it into any earthen vessel, and pour upon it as much strong hydrochloric, nitric, or sulphuric acid as will cover it (if* sulphuric acid is used it must bo diluted with an equal bulk of water); after standing 48 hours or more, add plenty of water, stirring it thoroughly, to remove the salts of iron; let it stand till all color has subsided, then draw off the clear liquid with a syphon ; add fresh water, and repeat the washing until ferrocyanide of potassium ceases to produce a blue precipitate, and the water drawn off ceases to redden blue litmus paper, then filter the product. This treatment extracts much of the iron from the Prussian blue, and takes away its liability to precipitate by longstanding. Next add and carefully mix 1 part oxalic acid to every 6 parts of Prussian blue; then dilute, by degrees, with water sufficient to make the blue ink any desired tint. The influences of air and dampness have a tendency to destroy the color of manuscript written with black ink, while the same influences tend to deepen and increase the color of the Prussian blue ink, This ink is only affected by continued exposure to light, which makes it fade in some degree; but it completely recovers its original depth of color by being put in a dark place.

2482. Mohr's Blue "Writing Fluid

2482.     Mohr's Blue "Writing Fluid. Triturate to a perfectly smooth paste, 6 parts pure Prussian blue, and 1 part oxalic acid, with a little water; then dilute with sufficient soft water to make it fluid.

2483. Runge's Black Writing Fluid

2483.    Runge's Black Writing Fluid. This is a cheap and good ink, and resists ordinary destructive agents well. It is perfectly liquid, scarcely thickens by age, deposits no sediment, and does not corrode steel pens. Digest 1/4 pound logwood in fine chips for 12 hours in 3 pints boiling water; then simmer down gently to 1 quart, carefully avoiding dust, grease, and smoke. When cold, decant the decoction, and dissolve in it by agitation 20 grains yellow chromate of potash; it will then be fit for use.

2484. Shellac Ink, or Coathupe's Writing Fluid

2484. Shellac Ink, or Coathupe's Writing Fluid. To 18 ounces water add 1 ounce powdered borax and 2 ounces bruised shellac, and boil them in a covered vessel, stirring them occasionally till dissolved. Filter, when cold, through coarse filtering paper; add 1 ounce mucilage; boil for a few minutes, adding sufficient finely-powdered indigo and lampblack to color it. Leave the mixture for 2 or 3 hours for the coarser particles to subside; pour it off from the dregs, and bottle it for use.