72 Mr. Hatchett's Experiments on the various Alloys , 
These experiments with lead, prove how destructive it is to 
the ductility of gold ; and that the properties of it, in this and 
many other respects, much resemble those of bismuth, except- 
ing that the latter has a more powerful effect, when reduced to 
vapour in the vicinity of melted gold. 
Bismuth, as well as lead, when combined with gold in certain 
proportions, produces some remarkable effects upon the texture 
and specific gravity of the latter metal ; and these effects are the 
most conspicuous, when either of the former metals is in the pro- 
portion of half a grain in the ounce Troy of gold alloyed with 
copper ; for then the alloyed gold becomes remarkably spongy, 
and suffers a very considerable diminution of specific gravity. 
GOLD ALLOYED WITH TIN. 
Experiment i. 
Eleven ounces one pennyweight and three grains of gold, 
23 car. 3+ grs. fine, being melted, eighteen pennyweights and 
twenty- one grains of pure grain tin were added, and, when 
well mixed, the whole was poured into a mould of iron. 
The bar was in some measure brittle ; but, as this appeared 
to be partly caused by the thickness, (£ of an inch,) the expe- 
riment was repeated as follows. 
Experiment 11. 
The same bar was melted again, and was cast in sand, so as 
to form a bar only ■§■ of an inch in thickness. 
This appeared to bend so easily, that it was passed between the 
rollers, but it then broke longitudinally into several pieces. 
The external colour of the bars, in both experiments, was 
very pale whitish yellow. 
