While natural unit systems simplify the form of each equation, it is still necessary to keep track of the non-collapsed dimensions of each quantity or expression in order to reinsert physical constants (such dimensions uniquely determine the full formula).
George Johnstone Stoney's unit system preceded that of Planck by 30 years.
He presented the idea in a lecture entitled "On the Physical Units of Nature" delivered to the British Association in 1874.
This natural unit system, used only in the fields of particle and atomic physics, uses the following defining constants:[23]: 509 where c is the speed of light, me is the electron mass, ħ is the reduced Planck constant, and ε0 is the vacuum permittivity.
Strong units are "convenient for work in QCD and nuclear physics, where quantum mechanics and relativity are omnipresent and the proton is an object of central interest".