HARDNESS, as recent correspondence in NATURE (vol. cvi., pp. 377, 440, 534, 599, 662, November, 192o–January, 1921) has shown, is a subject of interest to both the engineer and the physicist. Whatever ...
A material’s hardness relates to its mechanical resistance when subjected to mechanical indentation by another harder body. Diamond is considered the hardest natural material and is typically used for ...