Trade Wrinkles.

Red Copying Ink.—Dissolve 50 parts of extract of logwood in a mortar in 750 parts of distilled water without the aid of heat; add 2 parts of chromate of potassium, and set aside. After twenty-four hours add a solution of 3 parts of oxalic acid, 20 parts of oxalate of ammonium, and 40 parts of sulphate of aluminum in 200 parts of distilled water, and again set aside for 24 hours. Now raise it once to boiling in a bright copper kettle, add 50 parts of vinegar, and, after cooling, fill into bottles and cork. After a fortnight decant. This ink is red in thin layers, writes red, gives excellent copies in brownish color, and turns blackish brown upon the paper.—English Mechanic.

Violet Copying Ink.—Dissolve 40 parts of extract of logwood, 5 of oxalic acid, and 30 parts of sulphate of aluminum, without heat, in 800 parts of distilled water and 10 parts of glycerine; let stand 24 hours; then add a solution of 5 parts of bichromate of potassium in 100 parts of distilled water, and again set aside for 24 hours. Now raise the mixture once to boiling in a bright copper boiler, mix with it, while hot, 50 parts of wood vinegar, and, when cold, put into bottles. After a fortnight decant it from the sediment. In thin layers, this ink is reddish violet; it writes dark violet, and furnishes bluish violet copies.—English Mechanic.

An Improved "Graph."—The Papier Zeitung gives the following directions for making an improved « graph » :—Soak four parts of best clear glue in a mixture of five parts pure water and three parts ammonia (presumably liquor ammonia) until the glue is thoroughly softened. Warm it until the glue is dissolved, and add three parts of granulated sugar and eight parts of glycerine, stirring well and letting it come to the boiling point. While hot, paint it upon clean white blotting paper, with a broad brush, until the blotting paper is thoroughly soaked and a thin coating remains on the surface. Allow it to dry for two or three days, and then it is ready for use. The writing or drawing to be copied is done with the usual aniline ink upon writing paper. Before transferring to the blotting paper, wet the latter with a sponge or brush and clean water, and allow it to stand one or two minutes. Place the written side down and stroke out any air bubbles, and submit the whole to gentle pressure for a few moments, remove the written paper, and a number of impressions can then be taken in the ordinary way. When the impressions begin to grow weak, wet the surface of the « graph » again. This « graph » does not require washing off, but simply laying away for 24 to 36 hours, when the surface will be ready for a new impression.