DESCRIPTION OF PLATE 2. 



Slowly cooled alloys. 

 Percentage 



Formula, by weight. Magnification. Treatment, 



f Cu = 79 *7 



I. Cu 88 Sn 12 i g n — 20 *3 ^ diameters. Ammonia etch. 



2. Cu 86 bn 14 | Sn = 23 .3 



50 



Heat-oxidised. 



f Cu = 72 -8. 

 6. Uu 83 . 3 t5n 16 . 7 < Sn = 27 , 2 



300 



