>06 



BULLETEN 184, UNITED STA1E8 NATIONAL MUSEUM 



Ternera 2 meteorite, 40, 69, 115, 145. 

 Tests. (See Techniques, metallogra- 



phic.) 

 Thermal alteration, 91. 

 Thermal changes, cosmic, 76. 

 Thermal critical points for pure iron, 



27, 28. 

 Thunda ' meteorite, 61, 115, 155. 

 Tlacotepec 2 meteorite, 115, 143, 144. 

 Tocavita * meteorite, 63. 

 Toluca ' meteorite, 195. 

 Tombigbee River ^ meteorite, 115, 125, 



187. 

 Transformation. (See also Phases.) 

 alpha-gamma, 66. 

 delta-gamma, 26-28, 30, 57, 58, 60. 

 effect of nickel and cobalt on, 9, 44. 

 effect of on phosphorus, 69, 80, 81. 

 gamma-alpha, 9, 26-28, 30, 32, 36, 

 37, 39, 42, 43, 45, 46, 50, 51, 55, 

 56, 60, 62, 66, 67, 80, 82, 83, 86- 

 88, 90, 92. 

 gamma-delta, 26. 

 magnetic, 28. 

 of alloy, 31. 

 of kamacite, 15. 

 of taenite, 15. 

 retardation of, 55. 

 structural changes by, 45, 56, 67. 

 temperatures of, 43, 56, 69. 

 Transformation figures, 60. 

 Transformation in iron-nickel, 36, 37, 



43. 

 Transformation of iron, 26. 

 Transformation structure, 12, 56, 60- 



62. 

 Transformation temperatures of nickel- 

 rich ataxites, 69. 

 Transitional meteorites, 5, 7, 54, 64, 65. 

 Trenton i meteorite, 61, 62, 115, loo, 



198. 

 Trias summarized, 5, 47. 

 Troilite. (See also Sulphur.) 

 age of inclusions, 86. 

 alteration by heating, 78. 

 association of schreibersite with, 



19, 78. 

 association with graphite, 19, 21, 



53. 

 composition of, 18. 

 crystaUization of, 18, 53, 87. 

 definition of, 17. 



' Octahediite. 

 ^Ataxite, nickel-rich. 

 s Hexahedrite. 

 * Ataxite, nickel-poor. 



Troilite — Continued. 



expansion of, 87, 92. 



in ataxites, 13. 



in hexahedrites, 4, 13, 18, 52, 53. 



in octahedrites, 13, 17, 59, 87. 



needles of, 13. 



phosphide in, 78. 



properties of, 18, 86. 



relation to swathing kamacite, 13, 

 86, 87. 



sulphur synonymous with, 77, 86. 



tests for, 18, 95, 103. 

 Troilite nodule, displacement of, 92. 

 Troostite, 35, 36, 83, 84. 

 Tucson 2 meteorite, 25, 68, 115, 140. 

 Twinning, gamma, 51, 62, 82, 90. 



polysynthetic, 11. 

 Types, 4-10. (See also Ataxites, Hexa- 

 hedrites, Meteorites, Octahedrites.) 



Unidentified' meteorite, 70, 75, 115, 

 169, 194. 



Vogel mechanism, 57. 

 V^ogel's theory, 57, 58. 

 Vogel's views on plessite, 66. 



Walker County ^ meteorite. 36, 81, 92, 



115, 126, 167, 169, 172, 173. 

 Weathering, alterations by, 24. 



Wichita County ' meteorite, 22, 23, 115, 



174, 183. 

 Widmanstatten structure, artificial, 64. 



definition of, 4, 5, 54. 



form of, 6. 



genesis of, 45-47, 54, 58, 59, 66. 



in Horse Creek meteorite, 63, 64. 



structural changes in, 46, 47, 5G. 



Vogel's theory of, 57, 58, 66. 

 Wiley ' meteorite,' 65, 115, 137-139, 171. 

 VVood's Mountain ^ meteorite, 74, 93, 

 115, 159, 169, 189, 192. 



X-ray. (See under Techniques, metallo- 

 graphic.) 



Yanhuitlan • meteorite, 10. 



Youndegin • meteorite, 36, 115, 164, 165. 



Zacatecas ' meteorite, 63, 80, 115, 174. 

 Zones of alteration, 72, 76. 



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