iOOLOGy AND BOTANY, MICROSCOPY, ETC. 385 



GEOLOGY. 



Rocks of Italian Somaliland. — E. Manesse {Atti della Societa 

 Toscana, 1917, 31). Much information of interest to crystallographere 

 is included, together with some remarkable photomicrographs. 



On the Four Visible Ingredients in Banded Bituminous Coal : 

 Studies in the Composition of Coal, No. 1.— M. C. Stopes {Proc. 

 Roy. Soc, May 15, 1919, Series B, 90). The author recognizes 

 " fusain," " clairain," " durain," and " vitrain," as distinct microscopical 

 constituents in bituminous coal. 



The Chellaston Gypsum Breccia in relation to the Gypsum- 

 Anhydride Deposits of Britain. — B. Smith {Quart. Journ. Geol. Soc, 

 Sept. 5, 1919, 74). Microscopical evidence and photomicrographs are 

 appended. 



The Kelestomniae : a Sub-family of Cretaceous Cribimorph 

 Polyzoa.— W. D. Lang {Quart. Journ. Geol. Soc, Sept. 5, 1919, 74). 



METALLOGRAPHY, Etc. 



The Mechanical Properties of Steel, with some Consideration 

 on the Question of Brittleness. — W. H. Hatfield {Journ. Inst. 

 Mech. Eng., June, 1919). The conclusions arrived at show : — 1, That 

 general reliance cannot be placed upon any one test. 2. Real brittleness 

 occurs less frequently than is generally imagined. 3. Notched-bar 

 brittleness must be dissociated from true brittleness, since whilst the 

 former is always associated with the latter, the converse is not necessarily 

 true. 4. The tensile test is fundamental, the other being useful for 

 special purposes, though auxiliary. F. I. G. K 



The Acid Hearth and Slag. — J. H. Whiteley and A. F. Halli- 

 MOND (Iron and Steel Institute Meeting, May, 1919). Part I. Descrip- 

 tion of structure of slowly-cooled acid slags. Part II. Structure of the 

 hearth. Part III. Reactions in the molten slag. (With illustrations.) 



The Experimental Investigation of the Influence of the Rate of 

 Cooling on the Hardening of Carbon Steels. — A. M. Portevin and 

 M. Garvin (Iron and Steel Institute Meeting, May, 1919). 



Some Points in the Manufacture of Files. — G. Taylor (Iron 

 and Steel Institute Meeting, May, 1919). 



Macro-etching and Macro-printing. — J. C. W. Humprby (Iron and 

 Steel Institute Meeting, May, 1919). 



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