Bartholomew: Electricity and Color.

Scientific American 45, 29.7.1848

If white paper is moistened with a solution of the cyanide of potassium and a very minute portion of the salts of tin in a liquid state, and then submitted to the action of a galvanic battery, the paper will become a beautiful blue. Before submitting the paper to the action of the battery but prepared with the canide, it is a light green, but the galvanic current instantly changes this color to the blue. This is the principle of Mr. Barin's Printing Telegraph, and for which he has applied for letters patent at our Patent Office, which application is now the subject of a controversy with a Caveat of Professor Morse's and regarding which there have been some strange rumors in Washington about the secrecy of "the confidental archives." In 1832 a Mr. Davy, in London, proposed a printing telegraph upon the principle of the current changing the colors of chemically prepared fabrics. This is one evidence of the agency of electricity in the part of printing.

There is a certain style of calico printing founded upon a like principle, - it is named "steam and spirit colors." It is nothing more than to print certain substances upon cloth, in which portion of the salts of tin forms a leading ingredient, and afterwards roll the cloth upon cylinders, or steam cans, as they are called, and submit to gods to the action of steam heat for some hours. When the goods are printed the colors are scarcely disceranble but when they come out of the steam cans they are bright, full and beautiful. Every color, and every shade of color, is produced in this manner. We believe that electricity, (which we know is greatly developed in steam,) is the great agent in raising of spirit colors. In fact, the whole science of electrotyping, (the deposition of metals from their solutions by galvanism,) has a strong family resemblance to the electro telegraph printing; the cyanides are used most advantageously in both processes. In the steam colors of calico printing - the same agent is undoubtedly working mysteriously beautiful in the steam can and from a dull almost imperceptible blotch on the pieces when they go in the steam box, we behold them coming out clear and brilliant. The same agent undoubtedly presides over the manipulations of the dyer, but there are very few operatives who are acquainted with abstract science, although the majority of them well know that according to the degrees of heat to which a catchecu brown may be submitted, a difference of twenty or thirty shades is perceptible, and although they all well know that if chrome yellows are submitted to the action of hot lime water, a deep orange is produced, yet there are few who are aware of the oxidising proces in dyeing similar to the preparation of silver solutions for electro gilding.

The process of steam colors in printing, is applied to every kind of fabric, but perhaps to no branch of manufacture has it been or is it so advantageously and beautifully applied, as to the preparation of warps for carpets. - The invention of Whytock and the production of the finest velvet carpets of every pattern and by tehe use of only kind of weft, instead of one for every color as in the old process, is a very simple affair. The pattern of the carpet is printed like calicoes, full on the warp, rolled upon a roller and then submitted to the action of steaming. After this the warp is put in the loom and the weaver just weaves his cloth with two treadles like plain weaving.

R. Bartholomew.

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