Brass. 
79 
ihe copper, finds its way in vapour through the luting of 
the crucible-lids, and burns around them with the beauti- 
ful blue flame and dense white smoke peculiar to this 
metal. Of course* this is so much wasted. 
The heat required for brass-making is somewhat less 
than what would be necessary to melt large masses of 
copper, brass being the more fusible of the two, and, as it 
should seem, the vapour of zinc being able to penetrate 
copper as soon as it is softened by a full red heat. When 
the brass is judged to be complete, and the saturation of 
the copper with zinc to be as high as possible, the heat is 
increased to melt the whole down into one clean mass at 
the bottom, the crucibles are taken out and the metal 
poured into moulds. At Holywell, out of the six cruci- 
bles used to one furnace, the quantity of brass obtained is 
about as much as would fill one of them. This makes 
in subsequent manufacture a single large plate, which is 
manufactured in the same way as copper plate. Or, more 
accurately, from forty pounds of copper and sixty pounds 
of calamine, about sixty pounds of brass are obtained, be- 
sides the loss of a good deal of zinc by the unavoidable 
escape of much of it in form of vapour through the pores 
of the lute or the crucible-covers. 
The above is the usual process of brass-making in 
this country, and is essentially the same wherever this al- 
loy is manufactured ; but with some variation as to the 
choice of ingredients, their proportions, the time of fusion, 
the shape of the furnace and other smaller circumstances. 
At Goslar, in Saxony, where brass is largely made, the 
zinc is furnished not by a native calamine, but the cadmia 
or sublimed oxyd of zinc, which is collected for this pur- 
pose in a particular part of the chimnies of the reverbcra* 
tory furnaces in which the Saxon lead ores and blendes 
are roasted. 
A great variety obtains m the respective proportions of 
