MADDER PRINTING.

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consisting, for 300 metres of cloth, of 800 litres of water, 1-25 kilos, of sodacrystals, and 5 litres of bleaching-powder solution at 1-060 sp. gr.; tem-perature, 50°; time, thirty minutes. Again a washing in cold water, and,lastly, drying ends these operations.

When purples, lilacs, red, and black are printed on the same piece theclearing operations and ingredients used are the same as just described, butinstead of the bleaching-powder bath use is made of a bath made up of—Water, 1200 litres ; crystals of soda, 4 kilos.; potassa bleaching liquor(hypochlorite), 10 litres, at a sp. gr. of i'044; cloth, goo metres; temperature,38° to 44 0 ; time, twenty minutes ; washing and drying. The dry goods arecalendered,* next starched and blued, dried, and a second time calendered.Purple grounds and white designs require a larger quantity of ultramarine blue.

We have now to consider a totally different application of the colouringprinciples contained in madder, which may be explained in a few words, first,as follows:—Instead of printing on the mordant and immersing the preparedcloth bodily into a dye-beck containing the madder, the colouring matteritself is printed on to the cloth, after having been brought into a suitable stateof solution. In this instance we meet with three distindl modes of application;either the cloth itself is first thoroughly mordanted all over with acetate ofalumina or any other required mordant; or the colouring matter and themordant are so prepared as to form together the elements of the lake to befixed to the cloth; or, lastly, the lake previously and separately prepared, andin an insoluble state, is fixed by means of a plastic mordant, as, for instance,albumen. The first experimental trials in this direction were made in theyear 1827 by Messrs. Robiquet, Colin, Lagier, and Persoz ; but not before tenmore years had elapsed did M. Gastard, at Colmar, succeed in printing onthe large scale the colouring matters of madder upon previously mordantedcloth. It need hardly be observed that in this mode of proceeding there canbe no question whatever about the use of madder or any of its preparations,such as garancin, for instance, since all of these contain the ligneous inertfibre, and therefore the concentrated extradts of madder can only be appliedin this instance. M. Gastard has proposed two methods of operation for thispurpose—(1) the thorough mixing of colorin (a very rich alcoholic extradl ofmadder, formerly made by Messrs. Lagier and Thomas at Avignon) with gumor starch paste and acetate of alumina, and steaming after it has been printedon the cloth ; (2) the cloth is mordanted all over with acetate of alumina(preceded sometimes by an oiling operation, about which further details willbe given under the head of Turkey-red), the mordant is fixed as usual, thethickened colorin is printed on the fabric, which is next steamed, and afterwardscleared as for reds and rose-pinks. This operation may be also performedwith iron mordants as for brown ; in that case the ground colour of the clothwill be coloured by the mordant itself, but this buff may be removed bypassing the cloth through a tepid solution of bitartrate of potassa. Therather high price of the colorin has been the great obstacle in the industrialexecution of this process on the large scale. In the year 1838 M. Fauquet

* That is to say, undergo an operation which, in effedt, is the same as the ironing of linenmade up for use as clothing, but which in this instance consists in passing the goods betweentwo well-polished and bright cylinders made of copper or steel and heated by steam internally.