When a young woman was found lying on her hearth rug, foaming at the mouth on New Years Day of 1845, few would have guessed that the winding path leading up to her death would result in a mystery that would become entwined with one of the key moments in the history of communication as well as one of the earliest cases of murder by Prussic Acid. In the long catalogue of Victorian poisonings, the case of Sarah Hart remains prominent not just because of its twists and turns, but equally because of its long reaching influences on the adoption of a device that would help to shape the modern world.