Royal Irish Academy. 



AND II. 



Alloys of Copper and Zinc, and of Copper and Tin. 



67 



given are those which each prism just sustained for a few seconds before disrup- 

 tion. 



The copper used in these alloys was granulated, and of the finest "tough pitch;" 

 the zinc was Mossleman's, from Belgium ; and the tin " grain tin," from Corn- 

 wall. They were alloyed in a peculiar apparatus, to avoid loss by oxidation, and 

 the resulting alloy verified by analysis. 



No simple binary alloy of Cu -f- Zn or of Cu -j- Sn works as pleasantly in 

 turning, planing, or filing, as if combined with a very small proportion of a third 

 fusible metal, generally Cu -f- Zn -f Pb ; or Cu -f- Sn -j- Zn, as is known to 

 workers in metals. 



F2 



