276 Tables 307,308. 



SPECIFIC RESISTANCE OF METALS. 



TABLE 307 {concluded). 

 The resistance is here given as the resistance in microhms per cm. cube when the specific 

 resistance of mercury at 0° C. is taken as 94.1 microhms. 



Substance. 



Tantalum 

 Tellurium 

 Thallium 



Titanium 

 Tin . 



Zinc . 



State. 



Pure 

 Pure 



Trace Fe 



Liquid 



Temperature, -g^^^.^^^^^^ 



19.6° 



-183 



- 78 

 o 



91 



176 



-183 



-78, 

 o 



92 



igi 

 440 



14.6 

 21.5 

 4.08 

 11.8 

 17.60 

 24.7 

 3-'9 

 3.40 

 8.8 

 13.0 

 18.2 

 23.6 

 1.62 

 3-34 

 5-75 

 8.00 

 10.37 

 37-2 



Authority. 



Pirani. 



Matthiessen, 1852. 



Dewar, Fleming, Dickson, 18 



Shukow. 



D, F, D, 1898. 



De la Rive, 1863. 



TABLE 308. — Temperatuie Resistance Coefficients. 



If Ro is the resistance at the temperature to, and Rt at the temperature t, then Rt may over small 

 ranges of temperature be approximately represented by the formula Rt = R© ( i + at). 



Substance. 



Aluminum 



Bismuth . 

 Cadmium 

 Copper 



Gold . 

 " annealed 



Iron, pure 



— steel 



Lead . . 

 Magnesium 



Mercury* 

 Molybdenum 



Temperature. 



18-100° C. 

 to= 25° 



100 



500 

 O-IOO 



o-ioo 

 see p. 284-85 

 to = 100° 

 400 

 1000 

 18-100 

 to = 100° 

 500 

 1000 

 o-ioo 



to= 25° 



100 



500 



1000 

 glass, h'd 



blue 

 piano wire 

 18-100 

 o-ioo 

 to= 25° 

 100 

 500 

 600 

 0-15 

 to= 25= 



100 



500 



1000 



Substance. 



Nickel 



Palladium 

 Platinum 

 Silver . 



Tantalum 

 Tin . . 

 Tungsten 



Zinc . . 



Advance 



Constantin 



Manganin 



Temperature. 



0-100° C. 

 to= 25° 

 100 



500 

 1000 



O-IOO 



O-IOO 



O-IOO 



to= 25° 



100 



500 



O-IOO 



18-100 

 18-100 



to = 500° 



1000 



O-IOO 



lo 12 



so 

 100 

 200 



12 



25 



100 

 200 



500 



12 



25 

 100 



250 



475 

 500 



0.0062 

 0.0043 

 .0043 

 .0030 

 .0037 

 .0035 

 .0037 

 .0040 

 .0030 

 .0036 

 .0044 

 •0033 

 .0046 

 .0045 

 .0057 

 .00S9 

 .0040 



+ .000020 

 — .000008 

 — .000007 

 +.000007 

 + .000008 

 + .000002 

 —.000033 

 — .000020 

 +.000027 

 +.000006 



.000000 

 — .000042 

 — .000052 



.000000 

 — .000110 



I, Jager, Diesselhorst, Wiss. Abh. D., Phys. Tech. Reich. 3, p. 269, 1900; 2, Somerville, Phys. 

 Rev. 31, p. 261, 1910. 33, p. 77, 191 1 ; 3, Dewar, Fleming, 1S93, 1896; Strouhal, Barus, 18S3; 

 5, Glazebrook Phil. Mag. 20, p. 343, 1S85; 6, Pirani. 



Smithsonian Tables. 



• Mercury, R = Ro (i + .oooSgt +oooooit'). 



