Based on observations collected at the Germany-Spanish Astronomical Center, Calar Alto, Spain.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

Tables 2 and 3 are only available in electronic form at http://www.edpsciences.org

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

... reproduced

We have 47 stars common with the work of Edvardsson et al. (1993). We note that more metal-rich stars are included in our sample. The upturn in [Na/Fe] vs. [Fe/H], as observed by Edvardsson et al. is reproduced and reinforced. We confirm that the upturn is real (also see Feltzing & Gustafsson 1998).

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.