356 BLACK DYE 



substances for paving soom likely to be successful. During the last few years, several 

 experimental patches of asphalt-paving have been laid down in some of the most 

 active thoroughfares of the metropolis. Such paving recommends itself by being 

 much cleaner and quieter under heavy traffic than an ordinary granite pavement, but 

 has the disadvantage of becoming extremely slippery when the surface is slightly 

 moistened by rain. It is said, however, that this slipperinoss only lasts while the 

 pavement is moderately damp, and that but few horses fall on the asphalt during 

 either dry or thoroughly wet weather. The liquid Val de Travers asphalt, the 

 Limner asphalt, andBamett's liquid asphalt are all mixed with grit or sand, and thus 

 present rougher surfaces than those pavings which consist of asphalt alone such us 

 the ordinary compressed asphalt of the Val de Travers Company. See PAVEMENT, 

 ASPHALT and MASTIC. 



BITUMINOUS COAL Coal rich in bituminous matter. Pitch or caking coal, 

 cherry coal, splint coal, cannel coal, coking coal, and some others, are varieties of 

 bituminous coal. See COAL. 



BIXINE and BIXEINE. Two conditions of the colouring-matter of Arnatto, 

 according to Preisser. See ARNATTO. 



BLACK. AMBER. Pitch coal is so called by the amber-diggers of Prussia, 

 and it is manufactured by them into jet-like ornaments. 



BLACK BAND. A variety of the carbonate of iron, to which attention was first 

 called by Mr. Mushet at the commencement of the present century. The iron manu- 

 facture of Scotland owes its present important position to the discovery of the value 

 of the black-band ironstone. This ore of iron is also found in several parts of the 

 coal-basin of South Wales, and in the north of Ireland. The chemical composition of 

 the black-band iron ores will be given in connection with that of other minerals of 

 the same class. See IKON ORES. 



BLACK CHALK. A kind of clay containing a large amount of carbon. It is 

 found in Carnarvonshire and in the Island of Islay. 



BIiACX COAL Slate coal, cannel coal, and foliated coal, "were so called by 

 Jameson and other mineralogists of his day. 



BIiACK-COBAIiT OCHRE. See COBALT, EARTHY. 



BLACK COPPER. An impure black oxide of copper. See COPPER. 



BLAC2-C DYE. (Teinte noire, Fr. ; Schwarze Farbe, Ger.) Textile fabrics are 

 dyed by various processes, according to the quality of the black required, and the kind 

 of stuff on which the dye is to be produced. Under ANILINE-BLACK the process by 

 which that black dye is prepared is already described ; but the following process for 

 using an aniline-black as a dye for cotton goods by M. J. Persol properly finds its 

 place here : 



' Chemists have long tried to make use of the beautiful black precipitate produced 

 by the action of bichromate of potassa for the solution of certain aniline salts as a 

 dye for calicoes, but without success ; if the solution was concentrated, the black was 

 soon precipitated to the bottom of the bath ; if, on the other hand, it was dilute, the 

 black, owing to the absence of a sufficiently powerful oxidation, was not formed at 

 all, or in insufficient quantity. 



1 This trouble it was attempted to remove by cooling down the solutions nearly to 

 zero. But this produced another difficulty, the chromato of aniline crystallising out 

 at that temperature when the solutions were sufficiently concentrated to produce the 

 desired dye. Wherever these spots existed in the cloth on subsequent drying, a mutual 

 reaction took place between the constituents of the chromato of aniline, causing such 

 a rise of temperature as not unfrequently to set fire to the cloth. 



' To overcome these various difficulties the following expedients were adopted : 

 By means of a horizontal brush, to which a reciprocating motion was given in a vertical 

 direction, the solutions, either together or one after the other, were cast upon the 

 cloth, while tightly stretched, in the form of a fine spray. By this means, however 

 rapidly the reaction took place, it could not possibly do so until the solutions were 

 intimately mixed together upon the cloth, the latter being at the same time thoroughly 

 wetted with it. 



' The salts found to be most suitable for this reaction are the sulphate, hydrochlo- 

 ride, and the nitrate. No black is obtainable with the acetate ; and the tartrate, 

 oxalato, and citrate are more or less unfitted for the production of a good colour. 



' If a too nearly neutral solution is used there is great difficulty in producing the 

 colour ; if the solutions are too acid the black is formed so rapidly that the solutions 

 have not time to mix sufficiently and to penetrate the cloth. 



' As the result of numerous experiments with hydrochloric, sulphuric, and nitric 

 acid salts, the author came to the conclusion that: 1. The employment of neutral 

 aniline salts was ineffective. 2. The bi-acid aniline salts, especially the bi-sulphato, 

 give good results. Of tho tri-acid salts the hydrochlorido is tie best. 3. The sul- 



