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Spectra of the 2$\nu 3$ band of formaldehyde have been obtained with high resolution ($0.035cm-1$). Measurements were made with pathlengths from 8 to 24 m and at sample pressures from 0.1 to 0.3 mm of Hg. More than 300 lines were observed and assigned for $J\le 21$ and $Ka\le 9$. From these data the following constants were determined in $cm-1$: \begin{eqnarray*} \nu_{0} = 3471.718 \pm 0.004 \ A^{\prime\prime} -A^{\prime} = 0.0117 \pm 0.0005 \ B^{\prime} = 1.28100 \pm 0.00024 \ C^{\prime} = 1.11662 \pm 0.00024 \end{eqnarray*} The line strengths of 150 observed transitions were also obtained from the data. The strengths were analyzed to determine the band strength and the rotational factors. At $296\circ K$, the strength of the $2\nu 3$ band was found to be $15.7\pm 0.9cm-2$ $atm-1$. This paper presents progress of one phase of research carried out at the Jet Propulsion Laboratory, California Institute of Technology, under Contract No. NAS 7-100, Sponsored by the National Aeronautics and Space Administration.