Indicate the physical state (solid, liquid, or gas) for mercury given its melting point $\left(-40{ }^{\circ} \mathrm{C}\right)$ and boiling point $\left(357{ }^{\circ} \mathrm{C}\right)$ under the following conditions:
(a) $\mathrm{Hg}$ in ice water
(b) $\mathrm{Hg}$ in boiling water