and other Properties of the Copper -Antimony Alloys. 271 



violet colouring, both from the rest of the copper- antimony 

 series and from the alloys of other metals. 



As a typical set to work upon I selected the following 

 series : — 



N T 



1. 



Antimony 



100 pa 



rts. Copper 



parts 



M 



2. 



99 



95 , 



9 99 



5 



99 



99 



3. 



99 



90 , 



9 99 



10 



99 



H 



4. 



99 



85 , 



9 99 



15 



99 



99 



5. 



99 



so ; 



9 99 



20 



99 



}) 



6. 



99 



75 , 



9 99 



25 



99 



99 



7. 



99 



70 , 



9 99 



30 



99 



99 



8. 



99 



65 ; 



9 99 



35 



99 



9) 



9. 



99 



60 , 



9 99 



40 



99 



}9 



10. 



99 



55 , 



9 99 



45 



9> 



V 



11. 



99 



50 , 



9 99 



50 



99 



n 



12. 



99 



45 , 



9 99 



55 



99 



w 



13. 



99 



40 , 



9 99 



60 



99 



99 



14. 



99 



35 , 



9 99 



65 



99 



99 



15. 



99 



30 , 



9 99 



70 



99 



99 



16. 



99 



25 , 



9 99 



75 



99 



V 



17. 



?J 



20 , 



9 99 



80 



99 



9) 



18. 



99 



15 , 



9 ?J 



85 



99 



99 



19. 



99 



10 , 



9 99 



90 



%} 



99 



20. 



99 



5 , 



9 99 



95 



99 



I afterwards found it necessary to prepare two more, viz.: — 

 No. 10a, Antimony 49, Copper 51, which has the formula 

 Cu 2 Sb ; and No. 13a, Antimony 31*9, Copper 68'1, which 

 possesses the formula Cu 4 Sb. 



From the point of view of the metallurgist, the most inte- 

 resting fact connected with the electrical constants of the 

 alloys is the determination of the group to which, following 

 Matthiesen's classifications*, they belong. Are the alloys of 

 copper and antimony like, for instance, those of copper and 

 tin, " solidified solutions of one metal in the allotropic modi- 

 fication of the other "j and if so, is the curve of their electrical 

 resistance a continuous one, showing at first a rapid fall on the 

 copper side, and then turning and passing nearly horizontal 

 to the point representing unalloyed antimony ? 



The entire series of the copper-antimony alloys is unfortu- 

 nately very brittle, and therefore the preparation of wires is 

 out of the question, and the determination of the electrical 

 resistance of cast rods of metal is known to be attended with 

 many difficulties. I therefore determined to follow the course 



• Phil. Trans. British Association Reports, 1863. 



