[1] The formula was devised by Eugene Meyer of the Materials Testing Laboratory at the Imperial School of Technology, Charlottenburg, Germany, circa 1908.
Because of this, Meyer's law is often restricted to values of d greater than 0.5 mm up to the diameter of the indenter.
Despite this, it has been found that the values can be related using the equation:[5] Meyer's law is often used to relate hardness values based on the fact that if the weight is quartered, the diameter of the indenter is halved.
For instance, the hardness values are the same for a test load of 3000 kgf with a 10 mm indenter and for a test load of 750 kgf with a 5 mm diameter indenter.
This relationship isn't perfect, but its percent error is relatively small.