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pp. 417—432. 

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Bulletin de la Societe cV Encouragement i^our V Industrie 



Xationale, March 1897. 



Description of Plate 7. 



Fig. 1. Steel (containing about 0'6 per cent, of carbon), which 

 has been slowly cooled. Two main constituents : 

 "Ferrite" (pure iron), white patches; and "Pearlite" 

 (eutectic of iron and carbon), dark patches. The 

 lamellar structure of the latter is not clearly shown 

 under this magnification. x 110. 



Fig. 2. Appearance of the specimen shown in Fig. 1 under 

 a higher power. The lamellar structure of the 

 " pearlite " is now very noticeable. x 750. 



Fig. 3. Intercrossing needle-like (raartensitic) structure of 

 quenched (hardened) steel. The dark patches 

 (troostite), are not always present. x 750. 



Fig. 4. Lead-Bismuth alloy (cast on mica). White crystals 

 imbedded in a matrix of eutectic. x 110. 



Fig. 5. Gold-Lead alloy. Crystallites with their principal axes 

 lying in two directions at right angles. x 110. 



Fig. 6. Lead-Antimony alloy (cast on mica). White crystals 

 imbedded in a matrix of eutectic. x 110. 



Journ. Quekett Microscopical Club, Scr. 2, Vol. VIII. , No. 49, November 1901. 



