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the metallurgy and mineralogy of coinage, numbering about 400 
specimens. Examples are shown of coins made of gold, goloid, elec- 
trum, silver, billion, potin, aluminium, nickel, nickel alloy, bronze, 
gun-metal, bell-metal, copper, brass, iron, tin, pewter, lead, glass, 
and porcelain, and a few coins showing alteration, due to age and 
other agencies, as from bronze to malachite and azurite. 
Many of the coins are historical, such as the double ducat of 
Ferdinand and Isabella; the four daler piece of Sweden, weighing 
four pounds; siege and famine pieces of gun-metal; Arabian coins 
of glass; the ghost dollars of China, etc. This collection also illus- 
trates the various forms of striking coins from dies made of steel, 
iron, and wood; coins cast from a mold, and pressed such as the 
glass coins, etc 
