  One of the biggest mysteries of astrophysics is the question of how highly
energetic particles in relativistic jets and cosmic rays are accelerated.
Recently, it has been suggested that gravitational repulsion is the mechanism
responsible for these phenomena. The little known concept of gravitational
repulsion was first introduced by Johannes Droste in his Ph.D. thesis submitted
to H.A. Lorentz in 1916. It was written in Dutch. We provide a translation.
