390 



TABLE 395.— THERMAL ELECTROMOTIVE FORCE OF ZINC VERSUS 



PLATINUM 



Temperature versus emf 



TABLE 396.— CONDUCTIVITY AND RESISTIVITY OF MISCELLANEOUS ALLOYS 



Temperature coefficients 

 1 



Conductivity in mhos or 

 = p ( =p°(l +at — bf). 



ohms-cm 



= 7' = 7°(1 — at + bf) and resistivity in microhm — cm 



Metals and alloys Composition by weight 



Gold-copper-silver 58.3 Au + 16.5 Cu + 15.2 Ag 



" 66.5 Au-f- 15.4 Cu + 18.1 Ag 



" 7.4 Au + 78.3 Cu + 14.3 Ag 



Invar 



Welding iron 0.05% Cu 



Woods metal 56 Bi, 17 Cd, 14 Pb, 13 Sn. . . 



Brass Various 



hard drawn 70.2 Cu+ +29.8 Zn 



" annealed 



German silver Various 



[60.16 Cu + 25.37 Zn + 



" < 14.03 Ni + .30 Fe with trace 



I of cobalt and manganese 



Aluminum bronze 



Phosphor bronze 



Silicium bronze 



Manganese-copper 30 Mn + 70 Cu 



Nickel-manganese- 

 copper 3 Ni + 24 Mn + 73 Cu 



[ 18.46 Ni+ 61.63 Cu + 



Nickelin <^ 19.67 Zn + 0.24 Fe + 



[ 0.19 Co + 0.18 Mn 

 I 25.1 Ni + 74.41 Cu + 



Patent nickel j 0.42 Fe + 0.23 Zn + 



[ 0.13 Mn + trace of cobalt 

 f 53.28 Cu + 25.31 Ni + 



Rheotan 16.89 Zn + 4.46 Fe + 



[ 0.37 Mn 



Rheotan 53 Cu, 25 Ni, 17 Zn, 5 Fe. . . . 



Copper-manganese- 

 iron 91 Cu + 7.1 Mn + 1.9 Fe 



Copper-manganese- 

 iron 70.6 Cu + 23.2 Mn + 6.2 Fe. . 



Copper-manganese- 

 iron 69.7 Cu + 29.9 Ni + 0.3 Fe . . 



Therlo 85 Cu, 13 Mn, 2 Al 



Manganin 84 Cu + 12 Mn + 4 Ni 



Constantan 60 Cu + 40 Ni 



2.92 



190 



34 



bX 10" = 924. 



t b X 10" = 93. 



t b X 10"= 7280. 



SMITHSONIAN PHYSICAL TABLES 



