126 DESCRIPTIONS OF MINERALS. 
18°94. In the year 1822, a mass from Condoto was do- 
posited in the Madrid Museum, measuring 2 inches ana 4 
lines in diameter, and weighing 11,641 grains. A more 
remarkable specimen was found in the year 1827 in the 
Urals, not fur from the Demidoff mines, which weighed 113 
(more accurately, 11°57) pounds troy; and similar masses 
are now not uncommon. ‘The largest yet discovered weighed 
21 pounds troy ; it is in the Demidoff cabinet. 
Russia aifords annually about 35 ewt. of platinum, which 
1s about five times the amount from Brazil, Borneo, Colom- 
bia, and St. Domingo. Borneo affords about 500 pounds 
per year. 
The North Carolina platinum was found with gold in 
Rutherford County. It was a single reniform cranule, weigh- 
ing 2°54 grains. Other instances are reported from the 
Southern gold region. 
The infusibility of platinum and its resistance to the 
action of the air, and moisture, and most chemical agents, 
renders it of great value for the construction of chemical 
and philosophical apparatus. ‘The large stills employed in 
the concentration of sulphuric acid are now made of plati- 
num; but such stills are gilt within, since platinum when 
unprotected is acted upon by the acid, and soon becomes 
porous. It is also used for crucibles and capsules in chemi- 
cal analysis ; for galvanic batteries ; as foil, or worked into 
cups or forceps, for supporting objects before the blowpipe. 
It alloys readily when heated with iron, lead, and several of 
the metals, and is also attacked by caustic potash and phos- 
phoric acid, in contact with carbon ; and consequently there 
should be caution when heating it not to expose it to these 
agents. 
It is employed for coating copper and brass; also for 
painting porcelain and giving it a steel lustre, formerly 
highly prized. It admits of being drawn into wire of ex- 
treme tenuity. 
Platinum was formally coined in Russia. ‘The coins had 
the value of 11 and 22 rubles each. 
This metal fuses readily before the ‘‘compound blow- 
pipe ;” and Dr. Hare succeeded in 1837 in melting twenty- 
eight ounces into one mass. The metal was almost as malle- 
able and as good for working as that obtained by the other 
process ; it had a specific oravity of 19°38. He afterwards 
succeeded in obtaining from the ore masses which were 90 
