266 SUMMARY OF CURRENT RESEARCHES RELATING TO 



and a sensitive dry -plate in the camera will show a great contrast between 

 them. Without etching, whilst the object is still under the Microscope, 

 a drop of sulphuric acid (1 of strong acid to 3 of water) should be 

 placed on the surface, and from each sulphide particle a bubble of gas 

 will be evolved, but no gas will form over the pure silicate. This gas 

 can be recognised as H 2 S by cementing a small cell or ring of glass on 

 the polished specimen, and placing over this a cover-glass whose under- 

 side has been moistened with lead acetate. In a short time a dark stain 

 of lead acetate will form, easily recognisable under the Microscope. The 

 liquid may be removed in a capillary tube and further tested, with nitric 

 acid and bismuthate of soda, for a permanganate reaction. The areas 

 of sulphide and silicate can best be seen after heat-tinting the polished 

 specimens to a light-brown colour, when the patches appear relatively 

 light on a brown ground. 



Andrews, T. — Microscopic Observations on Naval Accidents. 



[The author describes his investigations of the cause of failure of the steel 

 connecting-rod of H.M.S. Bullfinch.'] Engineering, Dec. 2, 9, 16, 1904; 



Iron anil Steel Mag., ix. (Jan. 1905) pp. 163-8. 



Gledhill, J. M. — Development and Use of High-Speed Tool Steel. 



[A paper read at the Iron and Steel Institute Meeting, New York, Oct. 1904. 

 An historical and descriptive article, describing some of the most recent 

 improvements.] Iron and Steel Mag., ix. (Jan. 1905) pp. 19-44, 



with figs, and photomicrographs. 



S eaton, A. E., & A. Jude — Impact Tests on the Wrought Steels of Commerce. 



[The author describes bis experiments, and illustrates them by numerous 



photomicrographs.] Proc. Inst. Mechanical Engineers, 



read Nov. 18, 1904, 33 pp., 10 pis. and 8 figs 



