20 kil. cloth, mordant the same, dye with 1 kil. 200 grm. alizarine blue SRW.
Particular stress is to be laid upon the great fastness of the alizarine dyes against light and fulling. Besides, these dyestuffs contain nothing whatever injurious to the wool fiber. Sanders, which very much tenders the wool, as every dyer knows, can in all cases be replaced by alizarine red and alizarine orange, making an end to the spinners' frequent complaints about too much waste.
Alizarine blue in particular seems to be destined to replace indigo in the majority of its applications, having at least the same power of resisting light and acids, and relieving the dyer of the troublesome, protracted rinsings required for indigo dyed goods. Every piece-dyer knows that the medium and dark indigo blue goods still rub off, even after eight hours' rinsing; but alizarine blue pieces are perfectly dyed through and clean after one hour of rinsing. Another advantage of alizarine blue and the other alizarine dyestuffs is that they unite with all wood colors, as well as with indigo carmine and all aniline dyestuffs. A fine and cheap dark blue, for instance, is obtained by mordanting the wool as above stated and dyeing (20 kil.) in the second bath with 6 kil. alizarine WX and 2 kil. logwood chips; the wood is added to the bath together with the alizarine blue WX, and the best method is to put it into a bag which is hung in the bath.—D. Woll.-Gew.; Tex. Colorist.
Papier maché has come of late to be largely used in the manufacture of theatrical properties, and nearly all the magnificent vases, the handsome plaques, the graceful statues, and the superb gold and silver plate seen to-day on the stage are made of that material.
CEMENT PAVING.
The streets of "Old London" at the recent Inventions Exhibition at South Kensington were paved with a material in imitation of old, worn bowlder stones and red, herring-boned brickwork, all in one piece from one side of the street to the other. The composition is made by Wilkes' Metallic Flooring Company, out of a mixture consisting chiefly of iron slag and Portland cement, a compound possessing properties which won the only gold medal given for paving at that Exhibition. At the present time the colonnade in Pall Mall, near Her Majesty's Theater, is being laid with this paving, which is also being extensively used in London and the provinces for roads, tramways, and flooring; the composition is likewise sometimes cast into artistic forms for the ornamentation of buildings, or into slabs for roofing, facing, and other purposes. The subway from the Exhibition to the District Railway is laid with the same material.
The works of the Wilkes Metallic Flooring Company are in the goods yard of the Midland Railway Company at West Kensington. The Portland cement, before it is accepted at the works, is tested by means of an Aidie's machine. The general strain the set cement is required to bear is 750 lb. to the square inch. All samples which will not bear a strain of 500 lb. are rejected. The various iron slags are carefully selected, and rejected when too soft, and at the works a small percentage of black slag, rich in iron, is mixed in with them. The lumps of slag are first crushed in a Mason & Co.'s stone breaker, and then sifted through 1/8 in., 1/4 in., and 1/16 in. wire meshes into these three sizes for mixing. Next the granulated substance is thoroughly well washed with water to remove soluble matter and impalpable dust, and afterward placed where it is protected from the access of dust and dirt. The washing waters carry off some sulphides, as well as mechanical impurities. The Portland cement is not used just as it, comes from the works, but is exposed to the air in a drying room for about fourteen days, and turned over two or three times during that period. The slag is also turned over three times dry and three times wet, and mixed with the Portland cement by means of water containing 5 per cent. of "Reekie" cement to make the whole mass set quickly. The mixture is then turned over twice and put into moulds; each mould is first half filled, and the mixture then hammered down with iron beaters. The rest of the composition is then poured in, beaten down, and the whole mould violently jolted by machinery to shake down the mixture and to get rid of air holes. While it is still wet the casting is taken out of the mould, its edges are cleaned, and after the lapse of one day it is placed in a bath, of silicate of soda. Should the casting be allowed to get dry before it is placed in this bath, no good results would be obtained; it is left in the bath for seven days. When delicate stone carvings have to be copied, the moulds are of a compound of gelatine, from the flexible nature of which material designs much undercut can be reproduced. For the foregoing particulars we are indebted to Mr. William Millar, the working manager at West Kensington. Sometimes the composition is cast in large, heavy slabs, moulded on the top to resemble the surface of roads of granite blocks. A feature of the invention is the rapidity with which the composition sets. For instance, the manager states that a roadway was finished at the Inventions Exhibition at seven o'clock one night, and at six o'clock next morning four or five tons of paper in vans passed over it into the building, without doing any harm to the new road. In laying down roads, much of the preparation of the material is done on the spot, and the composition after being put down unsilicated in a large layer has the required design stamped upon its wet surface by means of wooden or gutta-percha moulds. As regards the durability of the composition, Mr. T. Grover, one of the directors, says that the company guarantees its paving work for ten years, and that the paving, the whole of the ornamental tracings, and some of the other work at Upton Church, Forest Gate, Essex, were executed by means of Wilkes' metallic cement three years ago, and will now bear examination as to its resistance to the action of weather. Some of this paving has been down in Oxford Street, London, for more than six years. Mr. A.R. Robinson, C.E., London agent of the company, states that the North Metropolitan Tramway Company has about 25,000 yards of it in use at the present time, and that the paving is largely used by the War Office for cavalry stables. The latter is a good test, for paving for stables must be non-slippery and have good power of resisting chemical action.