From 1848: Year of Revolution by Mike Rapport:
The speed with which the wave of revolutions swept across Europe was due to the wonders of modern technology. In 1789 it took weeks for news – carried, at its fastest, on horseback or under sail – for the fall of the Bastille to be relayed across Central and Eastern Europe. In 1848, thanks to steamships and a nascent telegraph system, reports were being heard within days or even minutes.