Abstract
The function h(x) appearing in the magnetic equation of state near the critical point, namely H=Mdelta h(x) has been constructed for the two- and three-dimensional Ising model. (h(x) is denoted by hI(x) in this case.) This has been achieved by first estimating the leading coefficients in the series expansions of hI(x) about x= infinity (critical 'isochore'), x=0 (critical isotherm) and x=-x0 (phase boundary), and then extrapolating these series with the aid of Pade approximants. hJ(x) is used to test various approximate forms for h(x), and is compared with experimental results for real ferromagnets and fluids. Finally hI(x) is used to compute the function mI( theta ) appearing in Schofield's parametric representation of the equation of state.