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Royal Irish Academy, 
colour uniformly diffused throughout the mass, so deep as to render 
the glass nearly opake. The experiment originated from a work- 
man in the glasshouse having dipped a heated copper ladle into a 
pot of fused glass. The copper ladle was melted ; the casting and 
annealing of the plates were proceeded with as usual ; and on their 
completion the workmen were surprised to find, that not only were 
grains of metallic copper imbedded in the substance of the glass, 
but bands uniformly coloured of a fine bright red, were distributed 
throughout the mass. 
“ The experiment of Guyton Morveau, being but a repetition of 
the accidental one made by the workman, seems to have but little 
engaged his attention, the colour being conceived to be due to an 
imperfect state of oxidation, as oxide of copper imparts to glass a 
greenish colour. 
“ It appeared to me, at first sight, that the red colour was 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 determine 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 dis- 
solve 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 dissolved, 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 me- 
tallic 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, — producing 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) 
disseminated throughout the mass. If the heat be increased, and 
the crucible containing the gold be left for some hours in the fur- 
nace, 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 crucible unaltered, owing 
to its infusibility. When charcoal is heated with glass, a large 
proportion is oxidated, the remainder presenting the appearance of 
a mechanical mixture. 
'' From these experiments it appears, that glass, at high tempera- 
tures, not only has the property of oxidating the metals, and form- 
ing a chemical compound with the oxide, but moreover, when the 
chemical affinity is satisfied, of dissolving the oxides, and probably 
the metals themselves when in a state of fusion ; the latter, on the 
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