POWER  OF  METALS  AJSD  ALLOTS  TO  CONDIJGT  HEAT. 
865 
Therefore  there  cannot  remain  a doubt  that  the  presence  of  tin,  zinc,  or  lead  in  the 
bars  exercise  a marked  action  on  the  conductibility  of  the  copper ; for  we  have — 
1 centim.  square  bar  of  rolled  copper  . 
7 millims.  square  bar  of  rolled  copper  . 
5 millims.  thick  ] , r.  ,,  , 
I bar  ot  rolled  copper  . . . 
1 centim.  wide  J 
1 centim.  square  bar  of  rolled  copper  and  tin  . 
1 centim.  square  bar  of  rolled  copper  and  zinc 
1 centim.  square  bar  of  rolled  copper  and  lead  * 
26-95 
19-12 
19-35 
26-45 
26-85 
23-05 
Alloys  in  which  there  is  an  excess  of  the  good  Conductor. 
Ha\ing  already  described  the  peculiar  properties  presented  by  four  of  the  bronze 
alloys,  viz.  those  of  Sn  2Cu,  Sn  3Cu,  Sn  4Cu  and  Sn  5Cu,  we  should  have  nothing  more 
to  add  to  them,  if  we  did  not  wish  to  illustrate  the  extraordinary  influence  which  tin 
exercises  on  the  conductibility  of  copper,  and  also  to  show  that  when  there  is  a great 
excess  of  a good  conductor  in  an  alloy,  it  overcomes  the  resistance  of  the  bad  conductor, 
and  in  consequence  the  conductibility  of  such  alloys  increases  with  the  proportion  of  the 
good  conductor. 
Obtained. 
Calculated. 
Silver = 
= 1000. 
Obtained. 
Calculated. 
Sn  =27-101 
5Cu  = 72-90  J 
6-60 
22-50 
207 
705 
Sn  = 15-681 
10Cu  = 84-32  J 
9-80 
23-90 
307 
749 
Sn  = ll-031 
15Cu=88-97J 
12-82 
24-50 
402 
768 
Sn=  8-51 
20Cu=91-49 
14-85 
24-81 
465 
00 
Sn=  6-831 
25Cu  = 93-l7 
15-15 
25-02 
475 
784 
Alloys  of  Bismuth  and  Antimony. 
These  alloys  also  show  a gradually  higher  degree  of  conductibility  as  the  number  of 
equivalents  of  antimony  increases  in  the  compound. 
Obtained. 
Calculated. 
Silver = 
= 1000. 
Obtained. 
Calculated. 
Bi  =62-26 
Sb=37-74  J 
1-97 
3-52 
62 
110 
Bi  =45-21 
2Sb=54-79  J 
2-45 
4-23 
76 
132 
Bi  =35-481 
3Sb=64-52j 
2-55 
4-63 
80 
145 
Bi  =29-201 
4Sb  = 70-80J 
3-05 
4-90 
96 
153 
Bi  =24*81 
5Sb=75-19 
3-45 
5-08 
108 
159 
* A metal  having  a very  low  conducting  power. 
