Carbon abundance relative to Fe distributions for the s-poor (upper panel) and s-rich (lower panel) stars. In each panel the dashed line represents the mean [C/Fe] abundance. The location of the stars selected for constructing the average s-rich and s-poor spectrum (see Fig. 7) has been indicated with dashed red and blue histograms, respectively. The dashed green histogram represents the location of stars with T_eff  >  6000 K, showing a rise in C with temperature.