The role played by émigrés in the history of Mesmerism and its dissemination in Europe and North America at the time of the French Revolution has received scant attention. This article will examine a group of ex-Mesmerists in exile, analyzing the use these practitioners made of magnetism outside of France in the fields of medicine, literature, philosophy, and politics. The practice of magnetism in emigré circles was highly secretive. And mesmerism itself was often subsumed in a more general critique of the Enlightenment and Freemasonry. Yet it was always part of that vast movement of scientific exploration of the « possible » that fascinated Montlosier in the same way as volcanism did, and that had exposed Charles Villiers to the philosophy of Kant. Endowed with a subversive character, animal magnetism, as it was re-elaborated in Swedenborg’s theories, had paradoxically never ceased to be practised by Joseph de Maistre, a partisan of the providential interpretation of the Revolution, and of ultra-royalist ideas. At the time of the Restoration, it was the principle of a Mesmerian universal harmony that encouraged the formation of a Holy Alliance.