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Using the hydrogen, krypton, and argon continua as a background, the absorption spectrum of CO molecule was investigated in the region 1070-2100A. Besides the bands previously reported by Hopfield, a new progression of bands was observed starting at 1618A. This was attributed to the transition: $d3\pi i\to X1\Sigma +$. The fourth positive system was extended up to at least $v\prime =20$. The dissociation energy of the $A\Pi 1$ state obtained by extrapolation of the $\Delta G$: v curve supports the value 11.11ev as D (CO) which was proposed by Gaydon and Penney.