io8 



NATURE 



[September 24, 1914 



manstatten, which are known to belong to the regular 

 octahedral system." ^ 



In a previous paper* the author described a steel 

 containing 055 per cent, of carbon, prepared in 1908 

 at the works of Igewsky in accordance with the direc- 

 tions of the author. This steel showed i throughout 

 its mass beautiful Widmanstatten figui-es, w-hich were 

 so developed that they were perfectly visible to the 



leave it on one side for the moment and to commence 

 with what might be termed a more or less detailed 

 "morphological" examination. From this it was not 

 difficult to see that the character of the Widman- 

 statten figures changed several times in a given area, 

 sometimes sho\ying triangles, sometimes squares, but 

 they are preciselv the figures that would be expected 

 in different sections of a regular octahedron the four 



Fig. 2. — Widmanstatten Structure in Taze-well 

 Meteorite. Section parallel to the Surface 

 of the Octahedron. Magnified 6 diameteis 

 and slightly reduced. 



Fig. 3. — Widmanstatten Structure in Carbon 

 Steel (Carbon, o 55 per cent.). Alloy 

 No. 8. Magnified 9 diameters and slightly 

 reduced. 



Fig. 4. — Swedish Iron heated to the point oT 

 Incipient Fusion (Osmond, " Sur la Cristal- 

 lographie du Fer "). Magnified 16 

 diameters. 



naked eye (Fig. i). The analogy between the struc- 

 ture of the alloy and that of the meteorites was so close 

 that the author considers that it may be regarded as a 

 synthetic production of a meteoritic structure, and 

 that it is fair to refer to this structure as the Widman- 

 statten structure (Figs. 2 and 3). 



Not only could the meteoritic structure be hence- 



systems of cleavages of which were parallel to the 

 four pairs of its surfaces, an arrangement known for 

 a long time in the case of meteorites.* Thus it was 

 the octahedral crystallisation of iron which was made 

 manifest by the distribution of the structural elements 

 between the cleavage planes during the recrystallisa- 

 tion.* The octahedral crystallisation of alloys of iron 



Fig. 5. — Widmanstatten Structure in Bronze, 

 containing 55'i per cent. Copper. Cooled 

 in Sand and Annealed (L. Guillet, " Les 

 Laitoni au Nickel"). Magnified 30 dia- 

 meters and slightly reduced. 



Fig. 6. — Widmanstatten Structure in Alloy of 90 

 per cent. Platinum and 10 per cent. 

 Aluminium (Chouriguine, "Sur les allia^es 

 du Platine avec I'Aluminium "). Magnified 

 50 diameters and slightly reduced. 



Fig. 7. — Widmanstatten Structure in Zinc, 

 cast and cooled slowly (G. Timoth^iefl). 

 Maenified (?) diameters and slightly 

 reduced. 



forth artificially reproduced at will, but the crystallisa- 

 tion of iron as well as its crystallography could be 

 easily studied from such examples. 



Although the question of the conditions which led 

 to the appearance of this structure seemed extremely 

 interesting, nevertheless it was considered wise to 



3 " Sur la CristallograDhie du Fer," Paris, 1900, p. 24, fies. 24 and 25. 

 The same observation was made in' 1905 by Profs. Arnold and Mc William in 

 their memoir, "The Thermal Transformation of Carbon Steel," Joum. of 

 the Iron and Steel Institute, 1905, No. II., p 35. 



4 "Sur la reproduction artificielle de la structure de Widmanstatten dans 

 ier au carbone," N. T. Belaiew, licviie de Metallurgie, 1910, p. 510. 



NO. 2343, VOL. 94] 



is generally admitted,^ and the greater part of the 

 iron-carbon diagram belongs to the type of diagrams 



' See Figs 7. 8, 9, 10, ti, 12, and 13, in the previously mentioned paper 

 they are also reproduced in M. Sauveur's book, " Tbe Metallography of 

 Iron and Steel." Lesson x., fies. 7-13. 



6 '• When a liquid or solid deposits successive! v feveral solid phases, the 

 secondary and tertiarv deposits often preferentially lodge between certain of 

 the cleavage planes (plans cristallographiques) of ihe primary deposit, and 

 thus illustrate its structure." " Sur la Cristallisation du Fer," Osmond et 

 Cartaud, Revue de Metallurgie, 1906, p. 658. — Note hy Editor, Proc. Inst, 

 of Metals. 



7 See also " Sur la crystallisation et structure des aciers refroidis 

 lentement," N. T. Belaiew, Revue de Metallurgie, 1912, p. 321. 



