Final concentration of the gold - the initial concert t rat ion being unity. 
PROFESSOR W. C. ROBERTS-AUSTEN ON THE DIFFUSION OF METALS. 399 
Fig. 3 (plotted from Table B). 
Fig. 4 (plotted from Table C). 
Platinum diffusing m lead for 6-96 days at 49 l.°C. 
be thought that this is an unnecessarily high temperature, but as some experiments 
are in progress in which lead alloys rich in gold are used, it was considered advisable 
to work at a temperature at which the entire series of alloys would melt, 
