4G 



ELECTROLYSIS. 



RESISTANCE OF ANNEALED PURE COPPER WIRES AND BARS continued. 



CONDUCTIVITY OF COPPER ALLOYED WITH FOREIGN SUBSTANCES. 

 PURE COI-PER = 100. (Matthiessen.) 



RELATIVE CONDUCTIVITY OF COPPER OF VARIOUS EXTRACTIONS. (Matthiessen.) 



Substances. 



1. Spanish, from Rio-Tinto, with 2 per 100 of arsenic, traces'! 



of lead, nickel, suboxide 



2. Russian, from Demidoif, with traces of arsenic, iron, nickel, ) 



suboxide / 



3. Tough cake, extraction not mentioned, with traces of lead.l 



iron, nickel, antimony, suboxide .. .. / 



4. Best selected, extraction not mentioned, with traces of iron,l 



nickel, antimony, suboxide .. ... .. / 



5. Australian, from Burra-Burra, traces of iron and suboxide .. 



6. American, from Lake Superior, traces of iron, suboxide,! 



and 0-03 per 100 of silver / 



