Fol. 15r

For the first time in the Codex a bat appears, an ideal model, according to Leonardo, for constructing a flying machine. He was not able to observe or study the bat in flight as he did with the kite, because the bat is too fast for the human eye, and in Leonardo’s day there were obviously no instruments to record it and slow it down. On the other hand, the anatomical observation of the animal showed him that the membrane of the bat’s wing provides a continuous surface and a good support, and this merits being copied. Next to that of the bat are drawings of other birds, all to be taken as models for the flying machine.

«Si ricordi che il detto uccello non deve imitare altro che il pipistrello perché le sue membrane fanno armatura, ovvero collegamento alle armature delle ali. E se tu imitassi le ali degli uccelli pennuti, vedresti che esse sono di ossa e nervatura più forti dal momento che sono traforate, cioè le penne sono disunite e trapassate dall'aria, mentre il pipistrello è favorito dalla membrana che lega il tutto e non è traforata»
(It should be recalled that said bird should not imitate anything but the bat, because its membranes form an armature, or connection of the armature to the wings. And if you were to imitate the wings of feathered birds, you would see that they are of bones and strengthening ribs that are stronger because they are perforated, that is, the wings are divided and passed through by the air, while the bat is assisted by the membrane that ties all together and is not perforated.)

NOTE. For each page of Leonardo’s Codex we provide a brief summary, with the quotation of one that page’s most significant passages edited in modern Italian, with an English translation.

translation by Kim Williams