TIME OF DISCOVERY OF THE METALS. 



Ill 



Infusible below a 

 red heat 



Silver, 



Copper, 



Gold, 



Cast-iron, 



Pure iron, 



Nickel, 



Cobalt, 



Manganese, 



Molybdenum, 



Chromium, 



Platinum, 



c. 



1020 

 1100 

 1200 

 1800 



F. 



1873 

 2012 

 2192 

 3272 



Highest heat of forge. 



Agglomerate, but do not melt in forge. 

 Fusible in the oxyhydrogen blowpipe. 



Specific gravities of metals at 15.5 C. 



Manganese, 8.00 



Cobalt, 8.54 



Molybdenum, 8.63 



Cadmium, 8.70 



Nickel, 8.80 



Copper, 8.96 



Bismuth, 9.90 



Silver, 10.50 



Lead, 11.45 



Mercury, 13.59 



Gold, 19.50 



Platinum, 21.50 



Time of discovery of the metals. 



These metals were known to the ancients, because they are either 

 found in a metallic state, or can be obtained by comparatively 

 simple processes from the oxides. 



Gold, 



Silver, 



Mercury, 



Copper, 



Zinc, 



Tin, 



Iron, 



Lead, 



y> I Latter part of the fifteenth centurv. 

 Bismuth, J 



Arsenic, 1694, by Schroeder. 

 Cobalt, 1733, by Brandt. 

 Platinum, 1741, by Wood. 

 Nickel, 1751, by Cronstedt. 

 Manganese, 1774, by Galm. 

 Molybdenum, 1782, by Hjelm. 

 Chromium, 1797, by Vauquelin. 



