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due to the actual solution of the copper in the metallic state, 
the globules of copper imbedded in the mass having been 
deposited from a state of solution, upon cooling. To deter- 
mine this, I mixed in different proportions with powdered 
glass, iron, lead, copper, silver, bismuth, antimony, tin, gold, 
platinum, in a minute state of division; and found that glass, 
when mixed with iron filings, will oxidate and dissolve 
almost as much iron, when mixed with it in the metallic state, 
as if it were mixed with it in the state of oxide. Of 
copper, only a small proportion is oxidated and dis- 
solved, imparting a green colour to the glass, while the rest 
remains disseminated throughout the glass in globules of 
copper and red streaks, which are probably the protoxide ; 
whereas lead (for whose oxide glass has such a strong 
affinity) oxidates but a small portion, when mixed with it in 
the metallic state, the rest being found imbedded in globules 
throughout its mass. Tin, antimony, and bismuth are more 
easily oxidized and dissolved than lead. Gold, when fused 
with glass, imparts to it a light greenish tinge, increasing in 
depth with the relative proportion of silica in the glass,—pro- 
ducing a deeper colour with the bisilicate than the silicate of 
potash, and still deeper when German glass (which contains a 
large proportion of silica) is employed ; globules of gold are 
found (as in the analogous cases of lead and copper) dissemi- 
nated throughout the mass. If the heat be increased, and 
the crucible containing the gold be left for some hours in the 
furnace, the glass assumes a pinkish hue, which is the colour 
imparted to it by the protoxide of gold. When platinum 
sponge is fused with glass, it sinks to the bottom of the cru- 
cible unaltered, owing to its infusibility. When charcoal is 
heated with glass, a large proportion is oxidated, the remain- 
der presenting the appearance of a mechanical mixture. 
‘‘From these experiments itappears that glass, at high tem- 
peratures, not only has the property of oxidating the metals, 
and forming a chemical compound with the oxide, but 
