specific Gravity, and comparative Wear of Gold. 187 
and copper, and of copper, which requires to be consi- 
dered. 
Gold alloyed with one-twelfth of silver, is of a fine but pale 
yellow ; it is very ductile; it is easily rolled, and may be stamped 
without being annealed ; it consequently does not require to be 
blanched ; and, after the complete process of coining, the sur- 
face and every part remains of an uniform quality, so that, by 
wear, it does not appear of different colours. 
These properties are certainly much to be valued ; but the 
objections to this kind of standard gold are, 
1st. The additional expense attending the use of silver as an 
alloy. 
2dly. The extreme pale yellow colour. And, 
3dly. That, from its great ductility, it is almost as liable to 
have the impressions which have been made upon it obliterated, 
as those which have been made upon fine gold. 
All things being therefore considered, gold alloyed only with 
silver, does not appear to be so proper for coin as may at first 
be imagined. 
Gold made standard by a mixture of equal parts of silver and 
copper, is not so soft as gold alloyed only with silver ; neither 
is it so pale, for it appears to be less removed from the colour 
of fine gold than either the former or the following metal. 
Gold alloyed with silver and copper, when annealed, does not 
become black, but brown ; and this colour is more easily removed 
by the blanching liquor, or solution of alum, than when the 
whole of the alloy consists of copper. It may also be rolled and 
stamped with great facility ; and, under many circumstances, it 
appears to suffer less by friction, than gold alloyed by silver 
only, or by copper. 
B b 2 
