305 



TABLE III. Second Series (32 specimens) arranged in order of 

 conductivity. 



Specification of compound with manufacturers' description 

 of mechanical quality of wire. 



19 9987 of No. 11 + 1-3 lead: fair 135-0 



8 999 copper-j-1 lead: fair 134-2 



18 995 copper-|-2-5 lead +2-5 iron: very good 131-5 



31 997 copper -f3 aluminium : good 130-2 



11 997-5 copper-f-2-5 iron : not very good 1297 



29 990 copper 4- 10 aluminium: good 1287 



9 999 copper + -5 lead+-5 silver : rather better than No. 8 128-0 



7 999copper+l silver: fair 1267 



13 1000 copper-f-2-5 protoxide of copper : very bad 122-5 



30 995 copper-f-5 aluminium : very good 122-5 



32 Pure copper : very good 120-9 



15 1000 of No. 4+2-5 protoxide of copper : better than No. 14, 



but not good 1197 



23 992 copper + 8 zinc: first-rate alloy 118-9 



2 998-7 copper + 1 -3 silver : fair, but rather frangible 1 177 



22 997-5 of No. 11 + 1-3 lead+1-3 zinc : very good indeed 117'6 



24 996 copper+4 zinc : moderately good 117'0 



6 998-7 copper-)- T3 tin : perhaps not quite as good as No. 5 ... 116-9 



12 9987 copper+1 -3 iron: frangible 1137 



27 994 copper+6 zinc : good 109-5 



16 997-5 copper+2-5 zinc : first-rate alloy 108-9 



4 998-7 copper 1 -3 lead : rather better than No. 4 105-8 



26 982 copper, 18 zinc : very good 102-3 



21 9987 of No. 11 + 1-3 zinc: very fair 95-2 



3 997-5 copper+2-5 lead : good, but requires care 94-5 



5 997*5 copper+2'5 tin : much the same as Nos. 3 and 4 91 -6 



10 Equal parts of Nos. 1 and 3 : bad, frangible 89-3 



17 995 copper+2-5 lead+2-5 zinc : very good 85-1 



25 986 copper +14 zinc: first-rate alloy 80-2 



20 997-5 of No. 11 +2-5 zinc: very fair 77'6 



1 997-5 copper 2-5 silver : fair, but rather frangible 69-8 



28 980 copper+20 aluminium : not very good 44-0 



14 1000 parts of No. 3+2*5 protox. copper; almost undrawable 



(too brittle to test). 



Specific 

 conducti- 

 vity. 



The alloys numbered 14 and 15 were prepared with a view 

 to testing the possible effect of a suboxide of copper mixed or com- 

 bined with the mass. Although they do not seem worse than others 

 of nearly the same metallic composition, it cannot be considered that 

 they demonstrate that oxygen exercises no influence, as the portion of 

 oxide introduced may have been reduced in the melting ; and indeed 

 it is quite possible that some accident in the melting may possibly give 

 rise to oxidation to a greater or less degree, and may cause some of 

 the irregularities and uncertainties which have been observed. On 

 this I may remark, that although I have found that no mechanical 

 alteration by hammering, twisting, &c. produces any considerable 



