Suppose that a new temperature scale has been devised on which the melting point of ethanol $\left(-117.3^{\circ} \mathrm{C}\right)$ and the boiling point of ethanol $\left(78.3^{\circ} \mathrm{C}\right)$ are taken as $0^{\circ} \mathrm{S}$ and $100^{\circ} \mathrm{S},$ respectively, where S is the symbol for the new temperature scale. Derive an equation relating a reading on this scale to a reading on the Celsius scale. What would this thermometer read at $25^{\circ} \mathrm{C}$ ?