specific Gravity , and comparative JVear of Gold. 79 
The bar thus formed was of a pale yellowish gray, approaching 
to a dull white ; it was very ductile, and, with great ease, was 
reduced by the rollers from \ of an inch to the thickness of a 
guinea. It was then cut without difficulty, by the punches, into 
blanks, and these were afterwards stamped with great ease, 
although they had not been annealed. 
Experiment 11. 
The same bar was again melted, and was cast in a sand 
mould ; it then appeared to be very brittle, but this, it was proved, 
was occasioned by the effects of the sand mould, which had 
rendered the metal porous ; for, when the parts had been ap- 
proached by previous hammering, the bar was rolled, and, in 
every respect, was found to be as ductile as in the former expe- 
riment. 
Experiment in. 
Eighteen pennyweights and ten grains of the fine gold being 
melted, one pennyweight and fourteen grains of cast-iron nails 
were added, and, when fused, the whole was cast in a mould 
of iron. 
This metal, in colour, much resembled the former; and was 
also perfectly ductile. 
Experiment iv. 
This was the same as Exper. hi. but thin plate cast-steel 
was employed, instead of cast-iron. 
The properties of this metal, in respect to colour, ductility, &c. 
resembled the former. 
Experiment v. 
To eighteen pennyweights and ten grains of fine gold, alloyed 
