Time resolved spectra of \beta Cep yield the following average results : T _ { eff } =24000 \pm 250 K , \log g = 3.91 \pm 0.05 and \xi = 8.1 \pm 0.9 km s ^ { -1 } .
N , O , Ne , Al , Si and S abundances are solar while C , Mg and Fe are slightly under-abundant .
Pulsational amplitudes of \Delta T _ { eff } \sim 700 K and \Delta \log g \sim 0.2 dex are found from H \beta .
The metal lines give similar amplitudes but centred on T _ { eff } \sim 25000 K. An upper limit of 1.0 km s ^ { -1 } to the variability of the microturbulence is derived from the Si iii triplet at 455 nm .
The radial velocity amplitude derived from the core of H \beta is \sim 15 \% greater than that from the metal lines .