,$$ $$\label{R_s-R_c}
R_\sigma = \frac{2}{3} \left[ (\zeta + 1)^2 - 1 \right] R_c\; ,$$ which will be exploited later.

Here it is important to make a remark regarding the quantity $s$, the gas solubility. Eqs. (\[zeta\]) and (\[s\]) give us $$\label{s(zeta)}
s = \frac{n_0 k T}{\Pi} \frac{1}{\zeta + 1}\; .$$ If Henry’s law is fulfilled, we have $\zeta + 1 = P_0/\Pi$ and, therefore, $$\label{s-Henry}
s = \frac{n_0 k T}{P_0}\; ,$$ $s$ is a tabular value defined only by the initial state of the solution (before the pressure drop).

Since we consider Sievert’s law, we have (see Eq. (\[P\_0-zeta\])) $\zeta + 1 = \sqrt{P_0/\Pi}$; thus instead of Eq. (\[s-Henry\]), we obtain $$\label{s-Sievert}
s = \frac{n_0 k T}{\sqrt{P_0 \Pi}}\; .$$ Here it is convenient to introduce constant $K$ as the coefficient of proportionality in Sievert’s law: $K \equiv n_0/\sqrt{P_0}$. It allows us to rewrite Eq. (\[s-Sievert\]) in the following form: $$\label{s-Sievert-K}
s = K \frac{kT}{\sqrt{\Pi}}\; .$$ Eq. (\[s-Sievert-K\]) shows us that in the case of Sievert’s law the solubility value $s$ depends on the final state of the solution. In the current paper a solubility value for Sievert’s law is understood as gas solubility at the final pressure $\Pi$ i.e. after 