PBOCEEDINGS OF THE SOCIETY. 119 



The outstanding features of some of the structures may now be very 

 l)riefly stated (the numbers referring to the annotated list). In No. 21, 

 in both sections, the interesting matter is tlie appearance of the minute 

 white rod-like crystals of iron phosphide. No. H is mostly remarkable 

 for the exceptionally perfect trianj^ular inclusion of binary eutectic at 

 the junction of three ferrite grains. Its area is no less than 2 sq. mm. 

 (approximately). The dove-grey manganese sulphide in No. 25 is very 

 clearly defined, and is particularly welcome from the microscopist's point 

 of view, because usually this constituent needs a magnification of the 

 order of 1000 to. recognize it, and even then it is very elusive. All the 

 other specimens are interesting for one reason oi- another, but these 

 remarks must only be taken as giving a few hints towards examining 

 the more unusual of them. In conclusion, it is a matter of great 

 satisfaction to us to have been favoured with such a gift from one of 

 the greatest masters of Metallurgical Research, in which the microscope 

 has played so great a part. 



ANNOTATED LIST OF THE .METALLURGICAL SPECIMENS PRE- 

 SENTED TO THE ROYAL MICROSCOPICAL SOCIETY 

 BY DR. J. E. STEAD, F.R.S. 



21. COAHULA MeTEOEITE AND COLUMNAR CRYSTALS. — He^t-tinted. 



liimi. : X 800. 



The blue and red background is a section through the columnar 

 crystals of ferrite. Miimte white spots, crystals of Fe.^F. 



Brf.: ■•' Micro-analvsis " (Stead), fig. 11)1. "Journal of the Iron 

 and Steel Inst." (Stead), No. L for 1915, p. 140. 



22. ToLUCA Meteorite. — Heat-tinted, llaff. : x 25. 



Background, saturated solution of Fe.^P in iron (1 "7 p.c. P). Bright 

 yellow areas, binary eutectic containing (U p.c. Fe.^P, 89 p.c. saturated 

 solution of FcgP in iron. 



Ref. : " Metallography " (Sauveur), p. 388 et i<ec[. 



23. AVhite Iron from Blast Furnace Bear.— Heat-tinted. Mag. : 



X 50 for general view. x 300 for the ternary eutectic. 

 Red = FegC. : blue = FcgP ; white = iron (ferrite) containing 

 some phosphorus in solid solution. Composition of ternary 

 eutectic as follows: — Fe = 91-19 p.c. ; P = 6*89 p.c. ; C = 

 1 • 92 p.c. 



Ref. : " Journal of the Iron and Steel Inst." (Stead), No. I. for 

 1915, p. 140, and coloured plates. 



24. (Irey Iron from Blast Furnace Bear. — Mag. : x loO. Gon- 



dituents : (Iraphite (dark plates), pearlite (laminated), ferrite 

 (plain), steadite (mottled). The last-mentioned is a eutectic 

 containing 10 p.c. P, 90 p.c. Fe, approximately. 



Ref. : "Metallography " (Sauveur), pp. 390 and 391, fig. 374. 



