14 



Day, etc. — Determination of Mineral 



the melting point up to 1600°, but is slightly concave upward. 

 The graph for lead is perfectly straight from the melting point 

 to 825°, and is represented by the formula : 



Kilogram-volume = 90-05 + 0-0108 t. 



The curve for the eutectic is slightly concave downward. 



At 650° the kilogram-volume of the eutectic, calculated on 

 the assumption that the volume is proportional to the weight- 

 percentage, should be 129*6. The value actually found, 

 129-88, is only 0'2 per cent higher than this. The difference 

 might easily be brought about by the combined errors of com- 

 pounding the alloy and making the three separate determina- 

 tions of volume. In other words, the mixing of the two 

 liquid metals in eutectic proportion is not accompanied by any 

 contraction or expansion in the total volume. 



Table I. 

 Density and Volume of liquid tin, lead, and lead-tin eutectic. 



Temp. 



Density- 



Kilogram-Volume 

















Tin 



Lead 



Eutectic 



Tin 



Lead 



Eutectic 



181 

 200 

 232 

 250 

 300 



(6-988)* 

 (6-982) 

 6-943 





(8-082)* 

 (8-063) 



8-011 

 7-965 



(143 

 (143 

 144 



1) 

 2) 

 03 





(123-7) 

 (124-0) 



124-83 

 125-55 



327 





10-686 









93-58 





350 



6 908 



10-658 



7-921 



144 



76 



93-83 



126-25 



400 



6-875 



10-597 



7-879 



145 



45 



94-37 



126-92 



450 



6-844 



10-536 



7-838 



146 



11 



94-91 



127-58 



500 



6-814 



10-477 



7-800 



146 



76 



95-45 



128 20 



550 



6.785 



10418 



7-764 



147 



38 



95-99 



128-79 



600 



6-755 



10-359 



7-731 



148 



04 



96-53 



129-34 



650 



6725 



10-302 



7-699 



148 



70 



97-07 



129-88 



700 



6695 



10-245 





149 



37 



9761 





750 



6-666 



10-188 





150 



02 



98-15 





800 



6-637 



10-132 





150 



67 



98-69 





850 



6 607 



10-078 





151 



35 



99-23 





900 



6-578 







152 



02 







950 



6-548 







152 



72 







1000 



6-518 







153 



42 







1100 



6459 







154 



82 







1200 



6-399 







156 



27 







1300 



6 340 







157 



73 







1400 



6-280 







159 



24 







1500 



6-221 







160 



75 







1600 



6-162 







162-29 







*Vicentini and Omodei. Atti R. Ace. Lincei. iii, pp. 235, 294, 321, 1887. 



