on some ancient metallic Arms and Utensils. 411 
the gun metal : but there was a much larger globule of silver 
in the coppel which contained the spear- head metal. 
As the only metal which appeared to contain more silver 
than the test itself was the spear-head, and as it emitted more 
fume than the rest, I repeated the process on this metal. 
The process of cupellation the second time, as before, caused 
the appearance of the white fume, and afforded a residue of 
silver, as before, in greater quantity than that of the test. The 
silver was determined in the most accurate way to amount to 
the proportion of fifteen grains in a Troy pound of the spear- 
head metal. There was no gold in this silver, for it dissolved 
totally in nitric acid, 
§ 5. Experiments with nitric Acid. 
,(a) A polished piece of each of the ancient metals was just 
wetted with nitric acid. Fumes of nitrous acid arose, and the 
part wetted became zvhite and corroded ; as is the case when 
the nitric acid has been applied in this manner to the allay of 
copper by tin. 
(6) On 300 grains of each of the above metals, in a small re- 
tort, were poured 1800 grain measures of nitric acid, purified by 
distillation from nitrate of silver, and of the specific gravity of 
1,330. The hydro-pneumatic apparatus being affixed, gene- 
rally from thirty to forty ounce-measures of nitrous gaz came 
over in the cold, in the course of two to three days. In this, 
time the whole, or at least the greatest part of the metal, was 
oxidified and dissolved ; there being a clear blue solution, with 
a copious white sediment, and sometimes a part of the undis- 
solved metal. 
By means of the fire of a lamp, more gaz came over, which 
