Nobel's furniture design was dynamite | Letters

One-legged stools | Mercia mudstone | Death by fish | Lancia cars | Naming your coldAll this discussion about the relative design and merits of three-legged stools (Letters passim) is as nothing compared with the so-called suicide stool, a one-legged stool designed by Alfred Nobel to prevent operators of the nitroglycerin reaction vats - part of the production process of his dynamite - falling asleep and allowing an exothermic runaway to occur, with the consequent explosion ruining everyone's day.Danny TanzeyThornton Cleveleys, Lancashire o Graham Thompson needs to be careful referring to the Keuper marl rock formation as a defining "north/south" feature (Letters, 21 October). I was recently admonished by a geology expert for using this term. "We now call it Mercia mudstone," I was told. But marl or mudstone aside, north of the Trent is True North.Martin RussellNottingham Continue reading...