The experiment P3.8.3.1 confirms the linear propagation of electrons in a field-free space. In this experiment, the Maltese cross is connected to the anode potential and the shadow of the Maltese cross in the electron beam is compared with the light shadow. We can conclude from the observed coincidence of the shadows that electrons propagate in a straight line. The Maltese cross is then disconnected from any potential. The resulting space charges around the Maltese cross give rise to a repulsive potential, so that the image on the fluorescent screen becomes larger.