  We report measurements of the thermopower $S$ and Nernst signal $S_{yx}$ in
graphene in a magnetic field $H$. Both quantities show strong quantum
oscillations vs. the gate voltage $V_g$. Our measurements for Landau Levels of
index $n\ne 0$ are in quantitative agreement with the edge-current model of
Girvin and Jonson (GJ). The inferred off-diagonal thermoelectric conductivity
$\alpha_{yx}$ comes close to the quantum of Amps per Kelvin. At the Dirac point
($n=0$), however, the width of the peak in $\alpha_{yx}$ is very narrow. We
discuss features of the thermoelectric response at the Dirac point including
the enhanced Nernst signal.
