These species are related by the degree of hydration.
2.
Another variable is the degree of hydration.
3.
The degree of hydration varies between perhaps 10 % and 25 %, with 20 % ( 4H2SO4 . H2O ) typical.
4.
In this low temperature regime that is dependent on degree of hydration, it has also been shown that proton conductivity is heavily dependent on humidity levels.
5.
This layer is about ten times as thick as the stratum corneum; however, diffusion is much faster here due to the greater degree of hydration in the living cells of the viable epidermis.