Energy Spectrum of the ${\pi }^{+}$ in $K^{+}\to {\pi }^{+}{\pi }^0{\pi }^0$

We have measured the low-energy portion of the ${\tau }^{\prime }$ spectrum in emulsion and the high-energy portion in a heavy-liquid bubble chamber. The final data consist of 642 events in emulsion and 3406 events in the bubble chamber. Fits have been made to several models, including the linear spectrum and the Brown-Singer $\sigma$ resonance. The data somewhat favor the $\sigma$-resonance model.