The Murders in the Rue Morgue C. Auguste Dupin and the Paris setting. Dupin reappeared in "The Purloined Letter", which Poe called "perhaps the best of my tales of ratiocination" in a letter to James Russell Lowell in July 1844. The original manuscript of "The Murders in the Rue Morgue" which was used for its first printing in "Graham's Magazine" was discarded in a wastebasket. An apprentice at the office, J. M. Johnston, retrieved it and left it with his father for safekeeping. It was left in a music book, where it survived three house fires before being bought by George William Childs. In 1891, Childs
Dupin cyclide of Dupin cyclides is invariant under the larger group of all Lie sphere transformations; any two Dupin cyclides are Lie-equivalent. They form (in some sense) the simplest class of Lie-invariant surfaces after the spheres, and are therefore particularly significant in Lie sphere geometry. The definition also means that a Dupin cyclide is the envelope of the one-parameter family of spheres tangent to three given mutually tangent spheres. It follows that it is tangent to infinitely many Soddy's hexlet configurations of spheres. A further special property of a cyclide is: An elliptic cyclide can be represented parametrically by the following formulas