ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 539 



paste with water and applied to the rotating wax discs with small brushes ; 

 rouge is used for finishing. A little water is required throughout the 

 polishing process. 



Polishing Machine for Metallographic Work.* — J. Aston describes 

 a new machine of the vertical spindle type, with rotation of the polish- 

 ing surface in a horizontal plane. The polishing discs are of sheet iron, 

 held in position by a magnetic clutch, and can be replaced without stop- 

 ping the machine. A number of V-shaped cuts are made near the cir- 

 cumference of the discs, and the points, bent down and sharpened, form 

 fasteners on which the cloth or other covering; material is hooked. 



o 



Brown, W. — Mechanical Stress and Magnetisation of Iron. 



Sci. Proc. Roy. Dublin Soc, xii. n.s. (1909) pp. 101-22, 175-89 (15 figs.). 



Dumas, A. — Chaleur specifique des substances ferromagnetiques, alliages de fer 

 et de nickel. 



[Sonie theoretical considerations are discussed, and a detailed description of 

 the method and apparatus used in the determination of the specific heat 

 of high-nickel alloys at different temperatures is given.] 



Arch. Sci. Phys. et Nat. (Bibliothe'que Univcrselle) 

 xxvii. (1909) pp. 352-82(3 figs.). 



Ross, A. D., & R. C. Geay — Magnetic Properties of certain Copper-alloys. 



Proc. Boy. Soc. Edinburgh, xxix. (1909) pp. 274-86 (5 figs.). 



Geay, J. G., & H. Higgiss — Low-temperature Experiments in Magnetism. 



Tom. cit., pp. 287-94 (7 figs.). 



Siemens, A. — Tantalum, and its Industrial Applications. 

 [Discourse delivered at the Royal Institution.] 



Nature, lxxx. (1909) pp. 290-2. 



Zoellneb, A. — Porzellan als Isolierungsmaterial vom physikalisch-chemischen 

 Standpunkte. 



[The microstructure of some samples of porcelain is described.] 



Elcctrotcchn. Zcitschr., xxix. (1908) pp. 1257-S (4 figs.). 



* Electrochem. and Metallurg. Ind., vii. (1909) pp. 15-16 (3 figs.). 



