1892.] 



On certain Ternary Alloy i 



23 



bulges observed due to the formation of the definite compounds AgZn 5 

 and Ag 4 Zn 5 ; a comparison of this with the aluminium-silver-lead 

 curve shows that the substitution of aluminium for zinc greatly 

 raises the curve, as previously found with aluminium-tin-lead and 

 aluminium-tin-bismuth, as compared with zinc-tin-lead and zinc-tin- 

 bismuth alloys respectively. 



On applying Stokes' second method to the above figures, a large- 

 scale plotting leads to the values A+A' = 80, B+B' = 3'5 at the 

 limiting point ; whence the composition for this point 



80 

 Lead . TT- = 40'0 



= 1-75 



Silver 



. 100-00 



representing a ratio between aluminium and lead close to that 

 indicated by the formula Pb 3 Al. The corresponding ratio found with 

 aluminium-lead-tin alloys, as above described, was near that indicated 



