And, certainly, the book need not have been one of Dostojewski's to excite this feeling in him. He chose the latter to give expression to a mood that may change according to what he reads, but undergoes no fluctuations in its ethical foundation. From other occasions we know how little ethics, that is conducted along systematic lines, signifies to him, and that he does not even include it in the sciences. But at the same time we see now that his inner life is dominated entirely by the ethical principle. His deep love of Art is characterized by it, and receives full satisfaction from the source of ethical joy of which Art is the centre. IV During the autumn of 1918 Einstein was feeling indisposed, and, on the advice of his doctor, did not leave his bed. When I entered his room, I saw at once that there was no reason for alarm, for pieces of paper covered with mysterious symbols were lying about, and he was absorbed in making additions to some of them. Nevertheless, I considered it my duty to treat him as a patient under medical care, and did not conceal my intention of leaving him after having inquired about his condition. But he would not accept my visit as a mere call to ascertain his progress towards recovery, and insisted that I should remain with him a while, to converse about amusing little problems as usual. I pointed out to him that there were two objections to this, the first being that he was unwell, and the second that I was intruding on his work. "How illogical!" he answered. "If I interrupt my work to chat with you, I am putting aside exactly what the doctor would deny me if I were to allow him. So, let us make a start. You have probably some conundrum weighing on your mind." "That may not be far wrong. I have been troubled by something in connexion with Kepler's second law. It almost robbed me of my night's sleep. My thoughts kept returning to a certain question, and I should like to know whether there is any sense in the question itself at all." "Let us hear it!" "The law in question states that every planet in describing its elliptic path, sweeps out with its radius vector equal sectorial areas in equal intervals of time. But this seems only half a law, for the radius vectors are only considered drawn from the one focus of the ellipse, namely, the gravitational centre. Now, another focus exists, that may be situated in space somewhere, perhaps far away in totally empty regions, if we assume the orbit to be very eccentric. My question is: What form does this law take if the radius vectors are drawn from this second focus and if the corresponding sectorial areas are considered, instead of these quantities being referred to the first focus exclusively?"