DESCRIPTION OF PLATE 3. 

 The same alloy chilled at different temperatures. 



Percentage 



Formula by weight. Magnification. Treatment. 



Cu 81 Sn 19 { = 30 -4 } Chi11 l ' 50 diameters. Heat-oxidised. 



5. „ „ Chill 3. 50 



6. „ „ Chill 5. 50 



