The best known classic electron models date back to the period between late nineteenth and early twentieth century, when issues were fermenting that would have led to the formulation of special relativity. These models are due to ABRAHAM and Eom~NXZ a, who were faced with the problem of the so-called electron self-energy, and who were particularly interested in the possibility of ascribing an electromagnetic origin to its mass. 2 In the traditional picture of electromagnetism, a well known difficulty arises in considering a point-like charged particle. In the case when it is at rest, for instance, the total energy of the CouLOM~ field diverges. The assumption that the electron has finite dimensions would appear as the easiest way to make this energy finite, as well as a means for calculating the reaction of the field produced by the moving charge. ABRAHAM conceived the electron as a rigid sphere with the charge uniformly distributed over its surface. Whereas LORENTZ considered it as a deformable object undergoing what is called the "LORENTZ-COntraction". Both theories would be in agreement with the available experimental data regarding the variation with the speed of the electron mass (assumed with an electromagnetic 6rigin). PO~YCAR~ a contributed to this subject with a clear analysis, showing, in particular, the need to take into account non-electromagnetic forces in the LORENTZ model. In the frame of the electron at rest, considered as a spherical deformable shell, the "Po~NCAR~ stress" holds together the charge distributed over the whole shell, balancing the mutual Coulombian repulsion between its distinct parts which tend. to expand it.