Scratch hardness Scratch hardness Scratch hardness tests are used to determine the hardness of a material to scratches and abrasion. The earliest test was developed by mineralogist Friedrich Mohs in 1820 (see Mohs scale). It is based on relative scratch hardness, with talc assigned a value of 1 and diamond assigned a value of 10. Mohs' scale had two limitations; it was not linear, and most modern abrasives fall between 9 and 10. Raymond R. Ridgway, a research engineer at the Norton Company, modified the Mohs scale by giving garnet a hardness of 10 and diamond a hardness of 15. Charles E.
Newton scale labels by two systems, one in arithmetic progression and the other in geometric progression, as follows: Newton scale The Newton scale is a temperature scale devised by Isaac Newton in 1701. He called his device a "thermometer", but he did not use the term "temperature", speaking of "degrees of heat" ("gradus caloris") instead. Newton's publication represents the first attempt to introduce an objective way of measuring (what would come to be called) temperature (alongside the Rømer scale published at nearly the same time). Newton likely developed his scale for practical use rather than for a theoretical interest in thermodynamics; he