In addition for T r < 27 / 32 = 0.84375 the liquid spinodal point occurs at a negative pressure, and the isotherm T r = 0.8 is included in Fig. 4 to illustrate this point. This means that some part of those liquid metastable states are in tension, and the lower the temperature the greater the tensile stress. Although this seems counterintuitive it is known that under some circumstances liquids can support tension. Tien and Lienhard noted this and wrote: