POWEE  OP  METALS  AND  ALLOYS  TO  CONDUCT  HEAT. 
361 
We  now  describe  the  most  important  series  of  this  class  of  alloys,  namely,  that  con- 
sisting of  those  composed  of  tin  and  copper. 
Copper  and  Tin, 
Formula  of  the  alloys 
and  per-centage. 
Temperature 
of  the  50  cub. 
cent,  before 
beginning. 
Temperature 
of  the  50  cub. 
cent,  after 
15  minutes. 
Conductibility 
found. 
Mean. 
Calculated. 
Silver  = 1000. 
Found. 
Calculated. 
Cu  = 34-98’ 
Sn  =65‘02 
Cu  = 21-21 ' 
2Sn  = 78-79. 
Cu=15-2] 
3Sn  = 84-79 
Cu=ll-86' 
4Sn=88-14 
Cu=  9-73  1 
5Sn  =90-27  J 
1 
> 
j 
'20-8 
L19-8 
r 19-4 
[19-5 
19-2 
[19-43 
'18-9 
19-0 
19-4 
19-7 
34-0 
33-1 
33-2 
33-2 
32-80 
32-85 
31- 7 
32- 1 
32-0 
32-4 
1.3-21 
13-3  j 
13-8' 
13-7  J 
13-61 
13-4 
12-8' 
13-1 
12-6  ' 
12-7  J 
13-25 
13-73 
13-50 
12-95 
12-65 
17-80 
16-08 
15-33 
14-92 
14-65 
415 
431 
423 
406 
396 
658 
504 
481 
468 
459 
It  is  very  interesting  to  observe,  that  although  these  alloys  contain  such  different 
quantities  of  copper,  viz.  from  9‘73  to  34-98,  and  this  of  a good  conductor  of  heat,  still 
no  influence  is  exercised  by  it  on  the  conductibility  of  the  alloys,  for  they  all  give  the 
same  results  as  if  the  square  bar  experimented  upon  were  composed  of  pure  tin. 
Another  fact,  which  increases  the  importance  of  the  bronze  alloys,  is  the  difference 
which  they  present  in  their  conductibility  when  they  contain  an  excess  of  copper,  not 
only  with  regard  to  the  above  series,  but  also  between  each  alloy,  all  of  which  have  a 
conducting  power  of  their  o-svn. 
Copper  and  Tin. 
Formula  of  the  alloys 
and  per-centage. 
Temperature 
of  the  50  cub. 
cent,  before 
beginning. 
Temperature 
of  the  50  cub. 
cent,  after 
15  minutes. 
Conductibility 
found. 
Mean. 
Calculated. 
Silver  =1000. 
Found. 
Calculated. 
Sn  = 38-21  1 
3Cu  = 6l-79  . 
Sn  =31-73 
4Cu=68-27 
Sn  =27-10 
5Cu  = 72-90 
> 
/21 
\20-6 
f 18-2 
J 18-0 
] 19-3 
i.18-4 
[17-7 
< 18-7 
1 17-9 
3^-7 
36-4 
23-1 
23- 1 
24- 25 
23- 30 
24- 2 
25- 3 
24-5 
15-7  1 
15-8  J 
4- 9  " 
5- 1 
4-95 
4-90  J 
6- 5  1 
6-6 
6-6  J 
15-75 
4-96 
6-6 
21- 37 
21-88 
22- 50 
494 
155 
207 
670 
686 
703 
The  results  obtained  with  Sn  4Cu  were  so  extraordinary,  that  the  bar  first  prepared 
was  remelted  and  cast,  from  a fear  that  there  might  be  in  the  mass  some  vacant  space 
or  hole  impeding  conduction ; but  as  it  yielded  the  same  results  when  submitted  to 
experiment,  we  decided  to  make  a new  bar,  weighing  most  carefully  the  metals  to  be 
used  and  also  the  bar  when  cast;  the  loss  being  only  0*5  per  cent,,  we  were  satisfied  that 
the  bar  was  sound,  and  still  it  gave  the  same  figures  as  the  bar  first  experimented  with  ; 
3 c 2 
