472 BRASS OF COAL 



for the passage of air or vapours ; the surface should bo thinly coated with loam, and 

 heated to about 200. 



Fenton's patent metal consists of copper, spolter, and tin : it has less specific gra- 

 vity than gun-metal, and is described as being ' of a more soapy nature,' by which, 

 consequently, the consumption of oil or grease is lessened. 



Many of the patentees of bearing metals assure us, that the metals they now use 

 differ very considerably from the statement in their specifications. Surely this requires 

 a careful examination. 



We exported of our BBASS MANUFACTURES, in 1864, as follows : 



Cwts. & 



Brass wire of all sorts, and manufactures of wire . 10,950 54,648 



Brass tubing 8,077 41,554 



Wrought brass of all other sorts, not being ordnance, \ OQA/IP IQTOI 



and not otherwise described . / ^' b * ( U7 ' 81 

 In the same year we imported : 



Brass manufactures, unenumerated .... 4,643 49,802 



Brass, old, fit only to bo re -manufactured . . . 3,085 6,325 



BRASS COLOUR, for staining glass, is prepared by exposing for several days 

 thin plates of brass upon tiles in the leer, or annealing arch, of the glass house, till 

 they are oxidised into a black powder, aggregated in lumps. This being pulverised 

 and sifted, is to be again well calcined for several days more, till no particles 

 remain in the metallic state, when it will form a fine powder of a russet-brown 

 colour. A third calcination must now be given with a carefully regulated heat, its 

 quality being tested from time to time by fusion with some glass. If it makes the 

 glass swell and intumesce, it is properly prepared ; if not, it must be still further 

 calcined. Such a powder communicates to glass greens of various tints, passing into 

 turquoise. 



When thin narrow strips of brass are stratified with sulphur in a crucible, and cal- 

 cined at a red heat, they become friable and may be reduced to powder. This being 

 sifted and exposed upon tiles in a roverberatory furnace for 10 or 12 days, becomes 

 fit for use, and is capable of imparting a chalcedony red or yellow tinge to glass 

 by fusion, according to the mode and proportion of using it. 



The glassmakers' red colour may be prepared by holding small plates of brass in 

 a moderate boat in a reverberatory furnace till they are thoroughly calcined. When 

 the substance becomes pulverulent, and assumes a red colour, it is ready for imme- 

 diate use. 



Brass colour, as employed by the colourmen to imitate brass, is of two tints the 

 red or bronze, and the yellow, like gilt brass. Copper filings mixed with red ochre, 

 or bole, constitute the former ; a powdered brass, imported from Germany, is used for 

 the latter. Both must be worked up with varnish after being dried by heat, and 

 then spread flat with a camel-hair brush evenly upon the surface of the object. The 

 best varnish is composed of 20 ounces of spirits of wine, 2 ounces of shellac, and 2 

 ounces of sandarach, properly dissolved. (See VARNISH.) Only so much of the 

 brass powder and varnish should be mixed at a time as is wanted for immediate use. 

 See BBONZE POWDER. 



BRASSES, COAL, or BRASS OF COAL, or BRASSEY COAX.. Names 

 given to iron pyrites found in the coal-measures. In 1872 it was estimated that the 

 following quantities were produced and used : 



NORTHUMBERLAND and DURHAM . . . 3,250 tons. 



YORKSHIRE 3,700 



LANCASHIRE 2,400 ,, 



STAFFORDSHIRE 3,700 



These sulphur ores are employed in Yorkshire, Lancashire, and on the Tyne, in the 

 manufacture of the protosulphate of iron (copperas.) For this purpose they are ex- 

 tended in wide-spread heaps, and thus exposed to atmospheric influences. The 

 result is the conversion of the sulphur into sulphuric acid, which re-uniting with the 

 iron forms the sulphate of the protoxide of iron, which is dissolved out and crj-stal- 

 lised. The presence of iron pyrites in coal (Brasses), often gives the tendency 

 to spontaneous combustion. A largo number of the ships which are sent from South 

 Wales to Chili, with coals, which are used for smelting the copper ores of that 

 country, take fire when they reach the tropics. This arises mainly from carelessness. 

 In the first place, the coals are not carefully selected. They are bought cheaply, 

 and being small, are put on board the ships, without being washed or picked, and 

 frequently damp. During the voyage, decomposition goes on, and by the time they 

 reach the warmer latitudes, a temperature sufficiently high to occasion actual com- 



