30 
MESSRS. C. T. HEYCOCK AND E. H. NEVILLE ON 
Table Ic. —Freezing Points of the Eutectic A.lloy of Silv^er and Copper. 
200 grams Silver. 
('■) 
(2-) 
Total weight of 
Percentage of 
copper present. 
copper. 
72 
26-47 
11 
7 i’05 
15 
27-02 
76-04 
27-5.5 
77-80 
28”ol 
79-11 
28-34 
82-13 
29-11 
87T5 
30-35 
55 55 
(3.) 
Atomic 
percentage of 
copper. 
(4.) 
Freezing point on 
the Centio-rade 
O 
scale. 
38-03 
783-44 
55 
(777-15) 
38-70 
780-4 
39-33 
(777-25) 
11 
779-11 
39-87 
/ 77-59 
40-27 
777-76 
41-18 
780-45 
781-49 
778-55 
42-63 
787-09 
55 
778-45 
'i'he ingot of alloy weighed 286'5 grams, while, the total weight of the metals used 
was 287T5. 
At temjieratures but little above the eutectic, the stationary temperature at the 
F.P.'^ lasted but a short time, so that there was some dano-er of readings these freeziim 
points too low ; to meet tins, nuclei of alloy were extracted from the crucible and 
dropped in just before the temperature fell to the freezing point. This method 
removes the risk of surfusion and slightly raises the observed F.P. 
There was an interval of a night between the earlier readings of this series and the 
last four, but the constants of the pyrometer were not re-determined. A change in 
the constants may be the cause of the fact that the lirst F.P. on the second day was 
a degree higher than the F.P. of the same alloy on the previous day. We have, 
therefore, in drawiim the curve of this series subtracted one decree from all the 
second day’s readings. 
* E.P. is “ freezing point.” 
