How does the role of public speech evolve in an age of technological transformation? Two literary and visual artefacts from the wars of nineteenth-century America pose this question, and offer insights into a chapter of media history that is still poorly understood. In the first, Richard Caton Woodville's War News From Mexico (1848), the ambivalent place of wartime voice takes centre stage. This most iconic of genre paintings records a foundational scene of US imperialism, and captures the public drama of national expansion. Its broader subject, however, is the social life of information. Woodville's image depicts news of Mexican surrender to Federal forces processing outwards from the central rectangle of crumpled text, intersecting with the geometry of the porch, the hotel, the post office insignia, the recruitment poster and the canvas itself. Through the isolated female onlooker and African American pair – who are all held, along with the viewer, at one remove from participation – we are shown how information excludes. Through the whisperer who relays the news to one of the hat-wearing men, we watch information being mediated.

But this is an image as much of performance as dissemination: upon the proscenium arch of the ‘American Hotel’ the public square becomes civic theatre, the setting for a ritual that Woodville wants us to imagine repeated in countless small towns as news of war diffuses through the republic. The waistcoated businessman proclaiming the news becomes a demotic mock orator of the Declaration and his newspaper – tattered from previous readings – is given life, its columns reanimated for the crowd.