Chapter XI (part 4)

Matter disappeared; its variety was replaced by a system of mutually related electric corpuscles and instead of the accustomed material world one deeply different—the electro-magnetic world—is envisaging itself to us.... But the recognition of the electro-magnetic world did not annihilate many unsolved problems and difficulties, and the necessity for a generalizing system was felt. In our difficult ascent we have reached the point [according to Prof. Oumoff] at which the road divides. One stretches horizontally to that plane p. 129 which has been pictured, another goes to the high summit which is already visible, and the grade is not steep. Let us look about us at the point which we have reached. It is very dangerous; not one theory only has suffered wreck there. It is the more dangerous that its subtlety is covered by the mask of simplicity. Its basis is the experimental attempts which gave a negative answer to the researches of careful and skilled experimenters. Prof. Oumoff shows the contradictions which were the outcome of certain experiments. The necessity to explain these contradictions served as the incentive to the discovery of the unifying principle: this was the principle of relativity . The deductions of Lorentz, which were made in 1909, and which in general had in view electro-optical phenomena only, gave the impetus to the promulgation by Albert Einstein of a new principle and to its remarkable generalization by the recently deceased Hermann Minkowsky. We are approaching the summit of modern physics. It is occupied by the principle of relativity, the expression of which is so simple that it is difficult to discern its all-important significance. It asserts that the laws of phenomena in the system of bodies for the observer who is connected with it, will be the same, whether this system is at rest, or is moving uniformly and rectilinearly. Hence it follows that the observer cannot detect by the aid of the phenomena which are proceeding in the system of bodies with which he is connected, whether this system has a uniform translational motion or not. Thus we cannot detect from any phenomena proceeding on the earth, its translational motion in space. The principle of relativity includes the observing intellect within itself, which is a circumstance of extraordinary significance. The intellect is connected with a complex physical instrument—the nervous system. This principle therefore gives directions concerning things proceeding in moving bodies, not only in relation to physical and chemical phenomena, but also in relation to the phenomena of life and therefore to the quests of man. It is remarkable as an example of a thesis, founded upon strictly scientific experiment, in a purely physical region, which erects a bridge between two worlds usually regarded as quite distinct. Prof. Oumoff gives examples of the explanation of complex phenomena by the aid of the principle of relativity. He shows further how the most enigmatical problems of life are explained from the standpoint of the electro-magnetic theory and the principle of relativity, and he comes at last to that which is the most interesting to us. Time is involved in all spatial measurements . 1 We cannot define the geometrical form of a solid moving in relation to us; we are always defining p. 130 its kinematical form. Therefore our spatial measurements are in reality proceeding not in a three-dimensional manifold, i.e., having three dimensions, of height, length and width, like this hall; but in a four-dimensional manifold: the first three dimensions we can represent by the divisions of a tape-measure upon which are marked feet, yards, or some other measure of length; the fourth dimension we will represent by the film of a cinematograph upon which each point corresponds to a new phase of the world's phenomena. The distances between the points of this film are measured by a clock going indifferently with this or that velocity. One observer will measure the distance between two points by a year—another by a hundred years.