264 



Table 272. 



RESISTANCE OF METALS AND 



The electrical resistance of some pure metals and of some alloys have been determined by Dewar and Fleming and 

 increases as the temperature is lowered. The resistance seems to approach zero for the pure metals, but not for 

 temperature tried. The following table gives the results of Dewar and Fleming.* 



When the temperature is raised above o° C. the coefficient decreases for the pure metals, as is shown by the experi- 

 experiments to be approximately true, namely, that the resistance of any pure metal is proportional to its absolute 

 is greater the lower the temperature, because the total resistance is smaller. This rule, however, does not even 

 zero Centigrade, as is shown in the tables of resistance of alloys. (Cf. Table 262.) 



Temperature = 



-80° 



Metal or alloy. 



Specific resistance in c. g. s. units. 



Aluminium, pure hard-drawn wire . 



Copper, pure electrolytic and annealed . 



Gold, soft wire 



Iron, pure soft wire .... 



Nickel, pure (prepared by Mond's process 

 from compound of nickel and carbon ^ 

 monoxide) 



Platinum, annealed . . 



Silver, pure wire 



Tin, pure wire 



German silver, commercial wire 



Palladium-silver, 20 Pd + 80 Ag 



Phosphor-bronze, commercial wire 



Platinoid, Martino's platinoid with i to 2% ) 

 tungsten ) 



Platinum-iridium, 80 Pt -+- 20 Ir 



Platinum-rhodium, 90 Pt -f 10 Rh . 



Platinum-silver, 66.7 Ag + 33.3 Pt . 



Carbon, from Edison-Swan incandescent ) 

 lamp ) 



Carbon, from Edison-Swan incandescent ) 

 lamp ) 



Carbon, adamantine, from Woodhouse and ) 

 Rawson incandescent lamp ) 



4745 



1920 



2665 



I3970t 



19300 



10907 



2139 



13867 



35720 

 15410 

 9071 



44590 



31848 

 18417 

 27404 



3834X103 

 6i68Xio3 



3505 

 1457 

 2081 

 9521 



13494 



8752 

 1647 



10473 



34707 

 14984 



43823 

 29902 

 14586 

 26915 



4046 X io3 

 3908 Xio* 

 6300X lo^ 



3161 



1349 

 1948 

 8613 



12266 



8221 

 1559 

 9575 



34524 



14961 



8479 



43601 



29374 

 13755 

 26818 



4092X10' 

 3955X108 

 6363X10' 



1400 



7470 



6133 

 1138 

 6681 



33664 

 14482 



8054 

 43022 



27504 

 10778 

 263 II 



4189X108 

 4054X108 

 6495X108 



• " Phil. Mag." vol. 34, 1892. 



t This is given by Dewar and Fleming as 13777 for 96°.4, which appears from the other measurements too high. 

 Smithsonian Tables. 



