BRA 



BRA 



it is well known, that certain additions 

 may be made to brandy which will very 

 much alter the frothing. After all that 

 has been done, it is still a difficult prob- 

 lem to determine, with perfect accuracy, 

 the strength of all kinds of made spirits, 

 by any shorter method than that of distil- 

 lation*, though the improved hydrome- 

 ters answer most of the purposes of trade 

 and revenue. The strength of the spirit, 

 of course, depends on the strength of the 

 wine with which it is made ; and this 

 again depends on the quantity of saccha- 

 rine mucilage contained in the must or 

 grape-juice, and the perfection of the fer- 

 mentation. Generally speaking, the 

 wines of hot climates furnish much more 

 spirit than those of colder? and sweet, 

 rich, well ripened grapes give much more 

 than the cold, sour, watery fruits. The 

 richest wines furnish as much as a third 

 of spirit; and the general average of the 

 wines in the south of France and Spain is 

 stated to be, by Chaptal, about a fourth. 

 On the other hand, some of the northern 

 wines (though perfect as wines) give no 

 more than a fifteenth of spirit. The manu- 

 facture of brandy in other countries very 

 closely resembles the French process 

 which we have just described. Thus, in 

 Spain, the still is filled to four-fifths of its 

 contents with wine, the capital luted on, 

 a fire kindled, and in about an hour and 

 a half the spirit begins to come over. 

 About a fifth of the entire quantity of 

 wine is proof spirit, in which olive-oil 

 sinks, and comes over fit to be used, with- 

 out farther process ; and as much of in- 

 ferior and weaker spirit comes over after- 

 wards, which is re-distilled and rectified. 

 When the wines are old, heavy, and oily, 

 and a fine clear spirit is wanted, at once, 

 water is added to the wine before dis- 

 tillation, to keep down the oil. The 

 principal distilleries in Spain are in Cata- 

 lonia. 



BRASS, in the arts, a metal much used 

 in various articles of manufacture ; it is 

 compounded of zinc and copper, in the 

 proportion of one part of zinc to three of 

 copper. It is of a fine yellow colour, and 

 more fusible than copper, and less liable 

 to tarnish from exposure to the atmo- 

 sphere. It possesses likewise a consider- 

 able degree of malleability and ductility, 

 and can be beat into thin leaves, and 

 drawn into fine wire. Its specific gravity 

 is greater than the mean specific gravity 

 of the two metals. See ZINC. 



Brass is manufactured in many coun- 

 tries ; but no where more extensively 

 and better than in England, in which both 



VOL. II. 



the materials are in great abundance. 

 The ores of zinc are several species erf 

 calamine and of blende, called by the mi- 

 ners Black Jack, which are found abun- 

 dantly in Devonshire, Derbyshire, and 

 North Wales, generally accompanying 

 lead ores. These are chiefly oxydes,. or 

 carbonated oxydes of zinc, and require a 

 previous calcination before they are fit for 

 brass-making. At Hollywell, in Flintshire, 

 the calamine, which is received raw from 

 the mines in the neighbourhood, is first 

 pounded in a stamping-mill, and then 

 washed and sifted in order to separate 

 the lead, with which it is largely admix- 

 ed It is then calcined on a broad, shal- 

 low, brick hearth, over an oven heated to 

 redness, and frequently stirred for some 

 hours In some places a conical pile is 

 composed of horizontal layers of calamine 

 alternating with layers of charcoal, the 

 whole resting on a layer of wood in large 

 pieces, with sufficient intervals for the 

 draught of air. It is then kindled, and 

 the stack continues to burn till the cala- 

 mine is thoroughly calcined. The cala- 

 mine, thus prepared, is then ground in a 

 mill, and at the same time mixed with 

 about a third or a fourth part of charcoal, 

 and is then ready for the brass furnace. 

 The brass furnace has the form of the 

 frustrum of a hollow cone, or a cone with 

 the apex cut off horizontally. At the 

 bottom of the furnace is a circular gnxte, 

 or perforated iron plate, coated with clay 

 and horse dung, to defend it from the ac- 

 tion of the fire. The crucibles stand up- 

 on the circular plate, forming a circular 

 row, with one in the middle. The fuel, 

 which in England is coal, is thrown round 

 the crucibles, being let down through the 

 upper opening or smaller end of the 

 cone; over this opening is a perforated 

 cover, made of fire-bricks and clay, and 

 kept together with bars of iron, so as to 

 fit closely. This cover serves to regulate 

 the heat in the following manner: the 

 draught of air is formed through an un- 

 der ground vault to the ash -hole, thence 

 through the grate and round the cru- 

 cibles, and through the smaller upper 

 opening into an area where the workmen 

 stand, which is covered by a large dome, 

 and a chimney to convey the smoke into 

 the outer air. When the draught is the 

 strongest, and the heat is required of the 

 greatest intensity, the cover is entirely 

 removed, and the flame then draws 

 through the upper opening of the fur- 

 nace to a considerable height into the 

 outer brick dome; when the heat is to 

 be lessened, the cover is put n, which 

 Nn 



