  We consider several classes of analytic parametrisations of hadronic
scattering amplitudes, and compare their predictions to all available forward
data (p p, pbar p, pi p, K p, gamma p, gamma gamma, Sigma p). Although these
parametrisations are very close for sqrt(s) > 9 GeV, it turns out that they
differ markedly at low energy, where a universal pomeron term ~log^2(s) enables
one to extend the fit down to sqrt(s)=4 GeV.
