14 AMERICAN MUSEUM (HIDE LEAFLETS 



Essential < 'onstituents. 



The iron of meteorites is always alloyed with from 6 to 20 per cent of 

 nickel. This " nickel-iron," as it is commonly called, is usually crystal- 

 line in texture, and when it is cut, polished and "etched" a beautiful 

 network of lines is brought out, indicating plates which lie in positions 

 determined by the crystalline character of the mass. This network of 

 lines constitutes what are called the Widmanstatten figures, from the 

 name of their discoverer. When these figures are strongly developed, 

 the meteoritic origin of the iron cannot be questioned, but their absence 

 does not necessarily disprove such an origin. Native iron of terrestrial 



WIDMANSTATTEN LINES, OR FIGURES 



Carleton Iron .Meteorite. Natural size. In this iron the plates are very thin. 



origin is extremely rare and has been found almost exclusively at Disco 

 Island and immediate vicinity on the west coast of Greenland. The 

 Disco, or Ovifak, iron contains less nickel than meteoritic iron, while 

 other terrestrial nickel-irons (i. e. awarnite and josephinite) contain 

 much more. Small quantities of metallic cobalt are also alloyed with 

 the nickel and a little copper is sometimes found in the same association. 

 Next to nickel-iron the mineral olivine, or chrysolite, is the most 

 important constituent. This is a silicate of magnesium, always con- 



