Dr. Pearson's Observations 
precipitate was produced on adding nitro-muriate of gold ; 
nor on adding it to tin dissolved by boiling in a large quantity 
of muriatic acid. 
The preceding analytical observations and experiments will, 
on examination, perhaps be found to contain sufficient evi- 
dence to demonstrate that each of the ancient metallic instru- 
ments contains copper and tin ; and they will also perhaps be 
found to prove, that these metals contain no other kind of me- 
tal, or other species of matter. But, in order to ascertain the 
proportion of the tin to the copper more accurately than I was 
able to do by analysis, and also in order to confirm or inva- 
lidate the evidence of analysis, I made the following synthe- 
tical observations and experiments. 
§ 6. Synthetical Observations and Experiments. 
Experiment 1. 50 grains of tin were united by fusion with 
1000 grains of copper. The ingot of this allay of twenty parts 
of copper by one of tin, when polished, differed from the celt 
metals in shade of the same colour ; these being much paler 
than this allay. It was a good deal harder, and not so tough 
as copper, but it was not so hard, and was more tough than 
the celt metals. Its fracture shewed also a more open grain 
than the old metals, and more inclining to the peculiar red 
colour of copper, instead of the brown and grey, or slate co- 
lour of the ancient metals. 
With nitric acid it afforded, like the ancient metals, a blue 
liquor, and white deposit of oxide of tin ; but in much smaller 
proportion than any of them ; not being more than seven per 
cent. 
Experiment 2. 100 grains of tin were united by fusion 
with 1500 grains of copper. This allay of fifteen parts of 
