Key points are not available for this paper at this time.
A universality hypothesis relates the amplitude of the singular parts of the coherence length and the specific heat (or surface tension). For the spin- Ising model it is exact in two dimensions and numerically accurate to within 1% in three. It is consistent with measurements on the "Ising-like" systems CO₂, Xe, and -brass and the "Heisenberg-like" systems RbMnF₃ and EuS to within experimental uncertainties (20%). It provides a sensitive and experimentally convenient indicator of symmetry ("universality") class.
Stauffer et al. (Mon,) studied this question.