Comment on gravity effects in light scattering experiments from simple fluids

The degree to which gravity-induced density gradients influence the determination of the critical exponent $\eta$ from light scattering experiments on simple fluids is carefully examined. As the critical temperature is approached from above, the scalling of the angular distribution of the scattering breaks down. Best fits of the angular distribution by a theory which properly scales yield apparent values of $\eta$ which depend on temperature. In experiments where $\eta$ is inferred indirectly by applying hyperscaling to measurements of $\gamma$ and $\nu$, there is an accessible region of reduced temperature where gravity systematically alters the results.