My craving for knowledge, always strong, became inordinate, probably because the acquisition of it was made so fascinating that I learned without real exertion. I began to find limits even to my father’s erudition, and chafed under them. He reviewed his Greek that he might impart it to us, as he had long before taught us Latin, and together we all three studied Spanish and Italian. I was not satisfied, for my desire for the one thing my father was unable to teach was not appeased by the twenty which he could. I begged for regular tuition, and, indulgent as he always was, he took us to Heidelberg, where I was enrolled in the gymnasium. Yet the long hours of separation that this entailed made little difference in our relations, since except for these we were inseparable. Whenever my school-work left us time to quit Heidelberg we made walking tours, and we availed ourselves of the summer holiday to see far-away lands. The great libraries were our chief goals, but everything interested us, from the archaic plough we saw in the field to the masterpiece of the gallery. I do not know whether I was dull for my years, but I do know that you were precocious and had no difficulty in keeping up with me in my studies. Indeed, thanks to your own brightness and to the long hours spent with my father while I was reciting, you went ahead of me in many respects. It makes me very happy now to think of what you two were to each other, and to know that you are so largely indebted to him for the depth and brilliance of mind that I hear so often commented upon. And I love you all the better because you made those years so happy to him by your love and companionship.