  Using Wald's formalism, we study the thermodynamics (first laws and Smarr
formulae) of asymptotically-flat black holes, rings etc. in a
higher-dimensional higher-rank generalization of the Einstein-Maxwell theory.
We show how to deal with the electric and magnetic charges of the objects and
how the electric-magnetic duality properties of the theory are realized in the
first laws and Smarr formulae.
