COPPER. 505 
fusible that the flame of a candle is sufficient to 
melt it. 
Copper likewise occurs mineralized by arsenic 
and other substances ; but that which more par- 
ticularly arrests our attention is the sulphate of cop- 
per , commonly called blue vitriol. This is a me- 
tallic salt formed of vitriolic acid and copper, which 
crystallizes in a very beautiful manner. It is very 
rarely found in Nature, being generally held in so- 
lution by the water which runs from copper-mines, 
and afterwards deposited either at the bottom or on 
the sides of the stream. When Dr. Brown, in the year 
1673, visited a famous copper-mine at Herngrund 
in Hungary, he saw two springs called the Old- and 
New-ziment, which were supposed by the inhabitants 
to possess the faculty of turning iron into copper. 
The prepossession of the country-people that this 
was really the case may be excused, when we 
consider that they must be totally ignorant of che- 
mical elective attraction, and that the vitriolic acid, 
having a stronger affinity for iron than copper, will 
always leave one to attack the other. This is ex- 
actly what occurs in Hungary, where old iron is 
thrown into the water of the spring, conducted into 
pits, and being there dissolved by the acid, is sus- 
pended in the water, whilst the copper is precipi- 
tated : the mud is afterwards collected, and being 
melted in a furnace, produces a very fine copper. 
From one hundred tons of iron, eighty-four and 
sometimes ninety tons of fine copper is obtained. 
We learn from Bishop Watson, that notwith- 
