Envelope pressure–temperature profiles for a sample of envelope properties. The blue and red curves represent the temperature at the top and bottom of the stable layer, respectively; for a saturated gas mixture, convection is shut off between the blue and red curves. In the absence of data, this figure assumes x_s = p_s/p and does not consider the temperature dependence of latent heat or the compositional dependence of the critical curve. See Fig. 7 for a conceptual sketch of the temperature structure below the envelope.