"Who cannot do as he desires, must do What lies within his power. Folly it is To wish what cannot be. The wise man holds That from such wishing he must free himself. Our joy and grief consist alike in this: In knowing what to will and what to do; But only he whose judgment never strays Beyond the threshold of the right learns this. Nor is it always good to have one's wish; What seemeth sweet full oft to bitter turns. My tears have flown at having my desire. Therefore, O reader of these lines, if thou Wouldest be good, and be to others dear, Will always to be able to do right." In Richter's works of Leonardo are many fables: "A razor, having come out of the sheath in which it was usually concealed, and placed itself in the sunlight, saw how brightly the sun was reflected from its surface. Mightily pleased thereat, it began to reason with itself after this fashion: 'Shall I now go back to the shop which I have just quitted? Certainly it cannot be pleasing to the gods that such dazzling beauty should be linked to such baseness of spirit. What a madness it would be that should lead me to shave the soaped beards of country bumpkins! Is this a form fitted to such base mechanical uses? Assuredly not. I shall withdraw myself into some secluded spot, and, in calm repose, pass away my life.' "Having therefore concealed itself for some months, on leaving its sheath one day and returning to the open air, it found itself looking just like a rusty saw, and totally unable to reflect the glorious sun from its tarnished surface. It lamented in vain this irreparable loss, and said to itself, 'How much better had I kept up the lost keenness of my edge, by practising with my friend the barber. What has become of my once brilliant surface? This abominable rust has eaten it all up.' If genius chooses to indulge in sloth, it must not expect to preserve the keen edge which the rust of ignorance will soon destroy." Richter also gives many pages of terse moral sentiments, showing that Da Vinci, in his more than thirty years of writing,--he began to write when he was about thirty,--had thought deeply and probably conformed his life to his thoughts. "It is easier to contend with evil at the first than at the last. "You can have no dominion greater or less than that over yourself. "If the thing loved is base, the lover becomes base. "That is not riches which may be lost; virtue is our true good, and the true reward of its possessor. That cannot be lost, that never deserts us, but when life leaves us. As to property and external riches, hold them with trembling; they often leave their possessor in contempt, and mocked at for having lost them. "Learning acquired in youth arrests the evil of old age; and if you understand that old age has wisdom for its food, you will so conduct yourself in youth that your old age will not lack for nourishment.