Measured data for alpha CO from:
Morrison, J.A., D.M.T. Newsham, and R.D. Weir 1968.  Equilibrium vapour pressures of carbon monoxide + nitrogen solid solutions.  Trans. Faraday Soc. 64, 1461-1469.
T(K)     P(bar)
51.29   1.51e-03
51.97   1.94e-03
52.50   2.34e-03
53.08   2.88e-03
53.71   3.57e-03
54.35   4.43e-03
55.30   6.04e-03
55.94   7.42e-03
56.20   8.07e-03
57.28   1.12e-02
58.30   1.52e-02
58.93   1.82e-02
59.21   1.97e-02
59.94   2.41e-02
60.46   2.78e-02
60.71   2.98e-02
60.79   3.04e-02
61.15   3.35e-02
61.37   3.54e-02
