"On Einstein's Theory of gravitation." By Prof. H. A. Lorentz.
I.
(Communicated in the meeting of February 26, 1916).
§ 1. In pursuance of his important researches on gravitation Einstein has recently attained the aim which he had constantly kept in view; he has succeeded in establishing equations whose form is not changed by an arbitrarily chosen change of the system of coordinates[1]. Shortly afterwards, working out an idea that had been expressed already in one of Einstein's papers, Hilbert[2] has shown the use that may be made of a variation law that may be regarded as Hamilton's principle in a suitably generalized form. By these results the "general theory of relativity" may be said to have taken a definitive form, though much remains still to be done in further
