Lecture I

To bring this home, I will adduce one more example. Even as we may think of the unit element, for the effects of Force in Nature, as a minute atom-like body which would be able to impart an acceleration of a centimetre per second per second to a gramme-weight, so too with every manifestation of Force, we shall be able to say that the force proceeds from one direction and works towards another. Thus we may well grow accustomed—for all the workings of Nature—always to look for the points from which the forces proceed. Precisely this has grown habitual, nay dominant, in Science. Indeed in many instances we really find it so. There are whole fields of phenomena which we can thus refer to the points from which the forces, dominating the phenomena, proceed. We therefore call such forces “centric forces”, inasmuch as they always issue from point-centres. It is indeed right to think of centric forces wherever we can find so many single points from which quite definite forces, dominating a given field of phenomena, proceed. Nor need the forces always come into play. It may well be that the point-centre in question only bears in it the possibility, the potentiality as it were, for such a play of forces to arise, whereas the forces do not actually come into play until the requisite conditions are fulfilled in the surrounding sphere. We shall have instances of this during the next few days. It is as though forces were concentrated at the points in question,—forces however that are not yet in action. Only when we bring about the necessary conditions, will they call forth actual phenomena in their surroundings. Yet we must recognize that in such point or space forces are concentrated, able potentially to work on their environment.