Relation of the CS molecular abundance to cloud physical parameters: kinetic temperature (left column), extinction (middle column), and molecular hydrogen density (right column). From top to bottom, the dataset is color-coded according to the molecular cloud of the points (first row), bins of kinetic temperature (second row), bins of extinction (third row), and bins of molecular hydrogen density (last row), as indicated in the corresponding legends. The black line in the top right plot shows the linear correlation between X(CS) and n(H₂) for the whole sample, with the correlation parameters indicated in the legend.