95 
specific Gravity , and comparative Wear of Gold. 
the different metallic substances which have been employed in 
the present experiments, appear to affect gold nearly in the 
following decreasing order. 
3. Antimony. 
4. Arsenic. 
5. Zinc. 
6 . Cobalt. 
7. Manganese. 
8. Nickel. 
9. Tin. 
10. Iron. 
11. Platina.* 
12. Copper. 
13. Silver. 
Before I conclude this section, I must observe, that the subject 
of alloys has not in general been Sufficiently investigated by 
chemists ; and I therefore should have been glad to have repeated 
the preceding experiments intirely in close vessels, and with 
many other precautions; but, from various circumstances, I 
have been obliged, for the present, to content myself with what 
.has been here related ; and, although I have not been able to do 
all I could have wished, I yet flatter myself that these experi- 
ments will tend to remove certain prejudices and erroneous 
opinions, and that they will be found to be of some utility. 
* Had the platina been quite pure, the compound metal would probably have 
possessed more ductility ; I cannot therefore take upon me to assert positively, that 
the place here assigned to platina, is precisely that which it ought to occupy. 
1. Bismuth. 
2. Lead. 
