specific Gravity , and comparative Wear of Gold. 69 
GOLD ALLOYED WITH LEAD. 
Experiment 1. 
To eleven ounces one pennyweight and three grains of gold, 
23 car. gj grs. fine, eighteen pennyweights and twenty-one 
grains of pure lead were added, and, being well mixed, the 
whole was poured into a mould of iron. 
The external colour of the bar was like fine gold, but rather 
more pale ; it had not the smallest degree of ductility, for it 
broke like glass. The grain was very fine, and of a pale brown 
colour ; it was devoid of metallic lustre, and had a porcellaneous 
appearance. 
Experiment 11. 
To eighteen pennyweights and ten grains of the fine gold, in 
fusion, 19 grains of copper were added, and, when the copper 
was melted and well mixed, 19 grains of lead were also added, 
to complete the standard proportion of alloy; the metal was 
then poured into a dry cupel. 
The button was, in external colour, like gold made standard 
by copper; but it immediately broke under the hammer, with 
an earthy fracture ; the grain, however, was not so close as that 
of the former experiment. 
Experiment in. 
Eighteen pennyweights of fine gold, were alloyed with one 
pennyweight and six grains of copper, after which, eight grains 
of lead were added. 
The colour of the metal was like that of the former, but it 
was perfectly brittle. 
The grain of the fracture was rather coarse. 
