An interesting paper published by Pomaranski et al. in Nature Physics 9, 353 (2013) demands further refinement of the microscopic spin hamiltonian of spin ice, Dy2Ti2O7 and Ho2Ti2O7 (DTO,HTO). In pursuing this project we have discovered a discrepancy between the susceptibility of HTO measured in the static approximation by neutron scattering and that measured on spherical crystals using bulk magnetisation. This experiment is designed to identify the origin of this difference by testing the validity of the static approximation, possible breakdown of the fluctuation-dissipation theorem and possible crystal shape-dependent physics in this system. The outcome will be a deeper understanding of the physics of the Coulomb phase in spin ice and an insight into Pomaranski's result.