684 • SUMMARY OF CURRENT RESEARCHES. 



minator, consisting of a cover-glass contained within a collar, is inserted 

 just above the object-glass, and is inclined so that rays entering an 

 aperture in the front of the collar are, in part, reflected by the cover- 

 glass (which can be rotated on a horizontal axis into the suitable 

 inclination), and thence pass downward through the object-glass and 

 illuminate the opaque object under examination. The rays finally 

 reaching the eye (returning through the object-glass much the way they 

 came) are for the most part transmitted through the transparent re- 

 flector. It was found that the quantity of light transmitted was 

 sufficient, even without the use of a lens, to strengthen the beam ; there 

 was no appreciable parallax, and even small microlithic felspars in 

 basalt could be seen, each glowing with its own colour and with sharp 

 margins. A notable advantage is that, with this mode of illumination, 

 the use of a polariser is unnecessary. When the source of light is 

 elevated above the horizontal level of the aperture in the illuminator, 

 so that the ray nearly reaches the glass at the polarising angle, the 

 polarisation is very complete. 



Barlow, A. E. — Microscopic Examination of Sections of Rocks associated with the 

 Iron-Ore Deposits of the Kingston and Pembroke Railway District. 



Geological Survey of Canada, Ann. Rep., XII. (Ottawa, 1902) 8vo. 



Report I. Appendix A, pp. 81-91. 



Campbell, E. D., & M. B. Kennedy — Probable Existence of a new Carbide of 

 Iron. 



[The authors give their reasons for the existence of Fe„C, in addition to the 



well-known Fe 3 C] Metallographist, VI. (1903) pp. 139-47. 4 figs. 



Chateliee, Le H., & M. Ziegler — Sulphide of Iron: its Properties and its 



m Conditions in Iron. Metallographist, VI. (1903) pp. 19-38, 28 figs. 



Dudley, P. H. — Rolling and Structure of Steel Rails. 



Metallographist, VI. (1903) pp. 111-29, 14 figs. 



Ewing, J. A., & J. C. W. Humfrey — Fracture of Metals under repeated 

 Alternations of Stress. 



Phil. Trans., Nov. 20, 1902; and Metallographist, VI. (1903) 



pp. 96-110, 15 figs. 



Gxjillet. L. — Sur la Micrographie des Aciers au Nickel. 



[The author's experiments confirm the results obtained by L. Dumas in 

 Annates des Mines, April 1902.] 



Comptes Bendus, CXXXVI. (1903) pp. 227-8. 



Howes, H. M. — Iron, Steel, and other Alloys. 



Metallographist, VI. (1903) pp. 179-95, 6 figs. 



M i e|r s, H. A. — Mineralogy, an Introduction to the Scientific Study of Minerals. 



[Described in the Geological Magazine for April 1903, p. 165, "as a really 

 readable work, setting forth the principles of scientific mineralogy, and 

 not unduly burdened with facts and technical details."] 

 • London (Macmillian & Co.) 1902, xviii. and 584 pp., 2 cold. pis. and 716 illus. 



Nickel Steel. Metallographist, VI. (1903) pp. 64-70, 6 figs. ; and Railroad Gazette, 



Aug. 8, 1902. 



Richards, M. A. — Photomicroscopy of Metals as practised by Steel Companies. 

 [Gives a useful account of methods in use.] 



Metallographist, VI. (1903) pp. 71-80, 8 figs. 

 Satjvettb, A.— On the Industrial Importance of Metallography. 



Journ. Franklin Inst, CLV. (1903) pp. 273-81. 



Satjveur, A., & H. C. Boynton — Note on the Influence of the Rate of Cooling 

 on the Structure cf Steel. Metallographist, VI. (1903) pp. 14S-55, 4 figs. 



