  This technical report is the union of two contributions to the discussion of
the Read Paper "Riemann manifold Langevin and Hamiltonian Monte Carlo methods"
by B. Calderhead and M. Girolami, presented in front of the Royal Statistical
Society on October 13th 2010 and to appear in the Journal of the Royal
Statistical Society Series B. The first comment establishes a parallel and
possible interactions with Adaptive Monte Carlo methods. The second comment
exposes a detailed study of Riemannian Manifold Hamiltonian Monte Carlo (RMHMC)
for a weakly identifiable model presenting a strong ridge in its geometry.
