IN NATURE of Jan. 23, 1926 (vol. 117, p. 117), I gave a description of a method of determining Hardness, in which a cone of the material to be tested was pressed against a hard surface (sapphire ...

Tungsten, with the chemical symbol W and atomic number 74, is located in the sixth period and group VIB of the periodic table. It possesses exceptionally outstanding physical properties, including a ...