Report upon dyeing cloth with Prussian blue.By Messrs. Merle, Malartic, Poncet, and Co., Saint Denis.

The London Journal of Arts and Sciences; and Repertory of Patent Inventions. Conducted by W. Newton, Civil Engineer and Mechanical Draftsman. Vol. XI. London, 1838.

The process of dyeing woollen goods with Prussian blue has particularly attracted the notice of chemists for the last twenty years. The experiments which have been made in this science, by Messrs. Ramond, Sonchon, Chevreul, and by one of our colleagues, M. Dumas, have completely resolved the scientific question of fixing Prussian blue upon wool. Some of these experiments have been made upon so great a scale, as to leave no doubt as to the practicability of its general application. The question is then to know, if dyeing with Prussian blue can sustain a competition with indigo, as regards price, beauty, solidity, and duration. It would, doubtless, be a great service rendered to the country, to be able to use advantageously, an article that may be easily made in all places and in all weathers, instead of a substance which is an exotic, and of a high price. Such a result would be well worthy of the rewards of the society. According to the testimony of your president, M. C. Baron Thenard, and by that of many other gentlemen of celebrity and good faith, who have worn cloths dyed by the Prussian blue of Messrs. Merle, Malartic, Poncet, and Co., this dyeing process wears at least as well as indigo; and the seams and other parts of the clothes that are exposed to continual friction do not become white, although the cloth is dyed in the piece. According to the report of the beauty of the colour, the specimens sent leave nothing to be desired. The reflection of the colour gives a vivacity and purity of tone which is never met with in indigo dyes, particularly in the clear shade. The chemical experiments that have been made with these specimens, have proved that the dye has really Prussian blue for its base, that it contained no indigo, that it was decomposable by caustic alkalies, but that it resisted very well the action of acids and of chlorine. Your commissioners, who have visited the establishment of Messrs. Merle, Malartic, Poncet, and Co., at St. Denis, have found it arranged for working upon a large scale. They have there seen pieces of cloth in the course of manufacture, and others entirely finished. These pieces appeared to them to be of a very fine colour, perfectly dyed, and the quality of the wool well kept. They have also been able to acquire proofs (by the register and correspondence that has been given to them ) that this establishment works for commerce, and that business is carried on with many important houses in the cloth trade. In this state of things, the committee would have wished to be able to propose a reward of the first order, for Messrs. Merle, Malartic, Poncet, and Co.; but these gentlemen wishing to keep for some time longer the secret of their application of dyeing; and the statutes of the society not allowing any reward to be granted, except to a perfect and complete communication of the whole process, your committee feel bound to make honourable mention of them, in order to reserve to them all their rights for a more important reward, when they shall deem it expedient to make their process known.
- Signed, Bussey Reporter, Bulletin de la Société d'Encouragement.