Figure 4.

Dependence of τ(P) for two different temperatures T = 31°C (solid black circles) and T = 34°C (solid red squares) on a linear-log plot. Error bars plotted are the estimated 10% error on the values of τ (see Fig. 2 for details). The low-pressure linear dependence on a linear-log plot suggests that τ(P) follows an exponential behavior. The discontinuous jump in τ(P) at a given temperature is marked by its departure from the initial exponential behavior.