British Association, 80th Report, Sheffield, 1910.] [Plate XI. 



No. 7. 

 An Iron-Carbon-Silicon Alloy, free from Phosphorus, made more stable by Sulphur. 



Broker. iup structure in the centre = the eutectic of two cementites, siiico-carbide 



and carbide. 

 Half- tone = the carbide cement ite. 

 Dark area— decomposed eutectic. 

 Light portion at right lower corner = crystallite of silico-pearlite. 



No. 8. 



Pure Iron-Iron Carbide Eutectic. the cooling of which was arrested before the 



complete decomposition of the Carbides into Austenite and Graphite. 



^mmi 



White =carbide of iron. Black lines=graphite. 



Half-tone = pearlite. 



