Three band systems of BaCl have been analyzed by means of spectrograms taken in the second order of two 21 foot gratings. The green system ($\lambda 5047$ to $\lambda 5322$) is a ${}_{}{}^2{}_{}{}^{}\Pi -{}_{}{}^2{}_{}{}^{}\Sigma$ transition and due to the nearly equal values of $\omega$ for the two electronic states is composed of only the $\Delta v=0, \pm 1$ sequences. There are two ultraviolet systems with (0,0) bands at $\lambda 3922$ and $\lambda 3692$, respectively. Both are presumably ${}_{}{}^2{}_{}{}^{}\Sigma -{}_{}{}^2{}_{}{}^{}\Sigma$ transitions and have broader Franck-Condon parabolas than the green system. The isotope effect of ${\mathrm{Cl}}^{35}$ and ${\mathrm{Cl}}^{37}$ is observed but in none of the systems could any bands be definitely attributed to barium isotopes other than ${\mathrm{Ba}}^{138}$. The dissociation products are discussed.

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