According to Einstein the laws of the physics do not depend of the place of observation. We have use this sentence to introduce the notion of small grains mass in the interactions between electron and proton “The quantum state and the doublets” or “Quantum state, the magnetism and the rotation”. Indeed such exchanges allow to have the same law for the attraction from the proton or the electron. In addition this introduce a way for the acceleration. The acceleration is clearly present when we consider the quantification of the space with one ½h quantum for the angular momentum and the other one ½h for the perpendicular direction to the angular motion. As a result it seems that this approach must shed light on the law of gravitation.