A direct and physically real relationship between "h" and "S" can be found by assigning a symbol to each microstate that occurs per mole, kilogram, volume, or particle of a homogeneous substance, then calculating the 'h' of these symbols. By theory or by observation, the symbols (microstates) will occur with different probabilities and this will determine "h". If there are N moles, kilograms, volumes, or particles of the unit substance, the relationship between "h" (in bits per unit substance) and physical extensive entropy in nats is: