Table 274. 267 



CONDUCTING POWER OF ALLOYS. 



This table shows the conducting power of alloys and the variation of the conducting power with temperature.* The 



,06 

 values of C„ were obtained from the original results by assuming silver = — ^ mhos. The coDductivity is taken 



as C,= C„ {i—ai+ifl), and the range of temperature was from o° to ioo° C. 



The table is arranged in three groups to show (i) that certain metals when melted together produce a solution 

 which has a conductivity equal to the mean of the conductivities of the components, (2) the behavior of those 

 metals alloyed with others, and (3) the behavior of the other metals alloyed together. 



It is pointed out that, with a few exceptions, the percentage variation between o^ and loo*^ can be calculated from the 



formula P-^P^ -^ where/ is the observed and /' the calculated conducting power of the mixture at 100° C., 

 and Pc is the calculated mean variation of the metals mixed. 



Alloys. 



Weight % Vo lume % 



of first named. 



Co 



aXio" 



5Xio9 



Variation per 100° C. 



Observed. Calculated 



Group i. 



SnePb 



Sn4Cd 



SnZn 



PbSn 



ZnCd2 



SnCd4 



CdPbe 



77.04 

 82.41 

 78.06 

 64.13 

 24.76 

 23.05 

 7-37 



83.96 

 83.10 

 77.71 



53-41 

 26.06 

 23.50 

 IO-57 



7-57 



9.18 

 10.56 



6.40 

 16.16 

 13-67 



5-78 



3890 

 4080 

 3880 

 3780 

 3780 



3850 

 3500 



8670 

 1 1870 

 8720 

 8420 

 8000 

 9410 

 7270 



30.18 

 28.89 

 30.12 

 29.41 

 29.86 

 29.08 

 27.74 



29.67 



30-03 

 30.16 

 29.10 

 29.67 

 30.25 

 27.60 



Group 2. 



Lead-silver (Pb2oAg) 

 Lead-silver (PbAg) 

 Lead-silver (PbAga) 



Tin-gold (Snt2Au) 

 " " (SnsAu) 



Tin-copper 



Tin-silver 



Zinc-copper t 



" t 



" t 



" t 



" " t 



95-05 

 48.97 



32-44 



77-94 

 59-54 



92.24 



80.58 



12.49 



10.30 



9.67 



4.96 



I-I5 



91.30 

 53-85 



36.70 



25.00 



16.53 



8.89 



4.06 



94.64 

 46.90 

 30.64 



90.32 

 79-54 



93-57 

 83.60 

 14.91 



12.35 



1 1. 61 



6.02 



1.41 



96.52 

 75-51 



42.06 



29-45 



23.61 



10.88 



503 



5.60 

 8.03 

 13.8b 



5.20 

 3-03 



7-59 

 8.05 



5-57 



6.41 



7.64 



12.44 



39-41 



7.81 

 8.65 



13-75 

 13-70 

 13-44 

 29.61 

 38.09 



3630 

 i960 

 1990 



3080 

 2920 



3680 



3330 



547 



666 



691 



995 

 2670 



3820 

 3770 



1370 



1270 

 1880 

 2040 

 2470 



7960 

 3100 

 2600 



6640 

 6300 



8130 



6840 

 294 



1 185 

 304 

 705 



5070 



8190 

 8550 



1340 

 1240 

 1800 

 3030 

 4100 



28.24 

 16.53 

 17-36 



24.20 

 22.90 



28.71 

 26.24 

 5.18 

 5-48 

 6.60 

 9.25 

 21.74 



30.00 

 29.18 



12.40 

 11.49 

 12.80 

 17.41 

 20.61 



19.96 



7-73 

 10.42 



14.83 

 5-95 



19.76 

 14-57 

 3-99 

 4.46 

 5.22 

 7-83 

 20.53 



23-31 

 11.8Q 



11.29 

 10.08 

 12.30 

 17.42 

 20.62 



NoTB. — Barus, in the " Am. Jour, of Sci." vol. 36, has pointed out that the temperature variation of platinum 

 alloys containing less than 10% of the other metal can be nearly expressed by an equation j/ =: — — m, where y is the 



temperature coefficient and x the specific resistance, m and « being constants. If o be the temperature coefficient at 

 0° C. and s the corresponding specific resistance, i (a -f- m) =: «. 



For platinum alloys Barus's experiments gave >« =: — .000194 and n =: .0378. 



For steel m =: — .000303 and « ^ .0620. 

 Matthiessen's experiments reduced by Barus gave for 



Gold alloys w =: — .000045, «= .00721. 



Silver »» = — .000112, « ^ .00538. 



Copper " m^ — .000386, n = .00055. 



• From the experiments of Matthiessen and Vogt, "Phil. Trans. R. S." y. 154. 



t Hard-drawn. 



Smithsonian Tables. 



