In a potentiometer experiment two cells of emf $E_{1}$ and $E_{2}$ are used in series and in conjunction and the balancing length is found to be $58~\mathrm{cm}$ of the wire. If the polarity of $E_{2}$ is reversed, then the balancing length becomes $29~\mathrm{cm}$. The ratio $\frac{E_1}{E_2}$ of the emfs of the two cells is}