Mean radius of large silicate grains (top) and mass ratio of silicate and carbon (bottom) versus extinction fit parameter c₂. The c₂ parameter describes a linear term in observations of the extinction curve between 115–330 nm (Valencic et al. 2004; Gordon et al. 2009). The dashed lines are straight-line fits of data belonging to the L_S -sample (filled circles in grey) and full lines are fits to the single-cloud sight-lines. Symbols same as in Fig. 6.