I am seized with astonishment, for I understand! There are a certain number of letters, general symbols which are grouped in all manner of ways, taking their places here, there, and elsewhere by turns; there are, as the text tells me, arrangements, permutations, and combinations. Pen in hand, I arrange, permute, and combine. It is a very diverting exercise, upon my word, a game in which the test of the written result confirms the anticipations of logic and supplements the shortcomings of one’s thinking-apparatus. “It will be plain sailing,” said I to myself, “if algebra is no more difficult than this.” I was to recover from the illusion later, when the binomial theorem, that light, crisp biscuit, was followed by heavier and less digestible fare. But, for the moment, I had no foretaste of the future difficulties, of the pitfalls in which one becomes more and more entangled the longer one persists in struggling. What a delightful afternoon that was, before my fire, amid my permutations and combinations! By the evening, I had nearly mastered my subject. When the bell rang, at seven, to summon us to the common meal at the principal’s table, I went downstairs puffed up with the joys of the newly-initiated neophyte. I was escorted on my way by a, b, and c, intertwined in cunning garlands. Next day, my pupil is there. Blackboard and chalk, everything is ready. Not quite so ready is the master. I bravely broach my binomial theorem. My hearer becomes interested in the combinations of letters. Not for a moment does he suspect that I am putting the cart before the horse and beginning where we ought to have finished. I relieve the dryness of my explanations with a few little problems, so many halts at which the mind takes breath awhile and gathers strength for fresh flights. We try together. Discreetly, so as to leave him the merit of the discovery, I shed a little light upon the path. The solution is found. My pupil triumphs; so do I, but silently, in my inner consciousness, which says: “You understand, because you succeed in making another understand.” The hour passed quickly and very pleasantly for both of us. My young man was contented when he left me; and I no less so, for I perceived a new and original way of learning things.