ABSTRACT
Leibniz called this the problem of the trajectory of a pocket watch, and he heard it from Claude Perrault (16131688), who was a well-known physician, mechanic, and musician in Paris. Imagine that you have a pocket watch on a cord and you put it along an edge of a table as shown in the picture. Now, if you drag the end of the cord along the other edge of the table, the watch will move on a tractrix. The edge of the table that the cord moves along is the asymptote to the tractrix.
