  Photospheric abundances are presented for 27 elements from carbon to europium
in 181 F-G dwarfs from a differential LTE analysis of high-resolution and high
signal-to-noise spectra. Stellar $T_{\rm eff}$ were adopted from an infrared
flux method calibration of Str\"{o}mgren photometry. Stellar log $g$ were
calculated from {\it Hipparcos} parallaxes and stellar evolutionary tracks.
Stellar space motions ($U, V, W$) and a Galactic potential were used to
estimate Galactic orbital parameters.
  Results of $\alpha$-elements -- O, Mg, Si, Ca, and Ti -- show [$\alpha$/Fe]
to increase slightly with decreasing [Fe/H]. Heavy elements with dominant
contributions at solar metallicity from the $s$-process show [$s$/Fe] to
decrease slightly with decreasing [Fe/H]. Scatter in [X/Fe] at a fixed [Fe/H]
is entirely attributable to the small measurement errors, after excluding the
few thick disc stars and the $s$-process enriched CH subgiants. Tight limits
are set on `cosmic' scatter.
  By combining our sample with published studies, thick disc stars are
identified by their $V_{LSR}$ in the range $- 40$ to -100 km s$^{-1}$. These
are very old stars with origins in the inner Galaxy and metallicities [Fe/H]
$\leq -0.4$. At the same [Fe/H], the sampled thin disc stars have $V_{LSR} \sim
0$ km s$^{-1}$, and are generally younger with a birthplace at about the Sun's
Galactocentric distance. In the range $-$0.35 $\geq$ [Fe/H] $\geq$ $-$0.70,
well represented by present thin and thick disc samples, [X/Fe] of the thick
disc stars is greater than that of thin disc stars for Mg, Al, Si, Ca, Ti, and
Eu. [X/Fe] is very similar for the thin and thick disc for -- notably -- Na,
and iron-group elements.
