Electric egg, also called de la Rive tube by the name of his inventor the physicist Auguste De La Rive (1801 - 1873), is used to study and to observe the rarefied gas electric discharge. It is a glass egg in which there are two iron small pole ending in two small globe that can be connected, through terminals, respectively to positive pole and negative pole. At the bottom of this instrument there is a tap to connect the container with vacuum pump.