58 
MESSRS. C. T. HEYCOCK AND F. H. NEVILLE ON 
fig. 6 above the complete curve, and on a larger scale. It is evident that this series 
confirms the earlier experiments, and puts the eutectic alloy exactly at Ag 3 Cu 2 . 
Fig. 6. 
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The numbers below the curve give the Centigrade temperature, those above the curve give the atomic 
percentage of copper. 
The theory of the subject, and many experiments of our own and of others, point 
to the conclusion that the eutectic alloy is not generally a compound, and hence should 
not have a formula. Some other evidence is, therefore, needed before we can accept 
Ag 3 Cu 3 as a chemical compound. 
The Silver-Lead and Silver-Tin Om'ves. (Figs. 7 and 8.) 
I'hese two curves resemble each other strongly. Lead and tin being non-volatile 
and easily fusible metals, the curve consists mainly of the silver branch, although the 
extreme right shows the depression produced in the freezing point of lead or of tin by 
the addition of silver, and also the eutectic phenomenon. 
The silver-lead curve is almost a straight line until 20 atoms of lead, but soon after 
this there begins a gradual, though marked, change in the curvature, with a point of 
inflexion at 50 atoms. In the tin curve the upper part is not straight, and the atomic 
