On October 23, 1635, German astronomer and mathematician Wilhelm Schickard, who constructued the very first mechanical calculator, passed away. His famous calculator was able to perform additions and subtractions. For more complicated operations, it provided so-called Napier bones, named after the Scottish mathematician John Napier, who came up with the idea of logarithms. Although it is widely believed that the first mechanical calculating device was created by the French mathematician Blaise Pascal in 1642. However, that distinction actually belongs to Wilhelm Schickard.
The millenium seemed to spur a lot of people to compile "Top 100" or "Best 100" lists of many things, including movies (by the American Film Institute) and books (by the Modern Library). Mathematicians were not immune, and at a mathematics conference in July, 1999, Paul and Jack Abad presented their list of "The Hundred Greatest Theorems." Their ranking is based on the following criteria: "the place the theorem holds in the literature, the quality of the proof, and the unexpectedness of the result."
The Euler Archive is an online resource for Leonhard Euler's original works and modern Euler scholarship. This dynamic library and database provides access to original publications, and references to available translations and current research.