When I worked in the Manuscript Division of the Public Archives of Canada (as it then was), the cross-written letter was the bane of my existence. People who needed to save the cost of posting an extra sheet of writing paper tended also to use cheap, gall-based ink and a nasty steel-nibbed pen, and the net result was illegible after a century in storage. Even when fresh, such missives could be puzzled out only by the eye of love.

The practice died out rapidly as postage costs dropped with the expansion of railways and the introduction of steam-powered mail ships.