There can be no voice where there is no motion or percussion of the air, there can be no percussion of the air where there is no instrument, there can be no such thing as an immaterial instrument; and this being so, a spirit can have neither voice, nor shape, nor force; and if it assumes a shape it can neither penetrate nor enter where the issues are closed. If any one were to say that a spirit may take bodies of various shapes by means of concentrated and compressed air, and by means of this instrument speak and move with force--I reply to this argument that where there are no nerves or bones, no force can be expended in any movement made by these imaginary spirits. {193} BIBLIOGRAPHICAL NOTE AND TABLE OF REFERENCES BIBLIOGRAPHICAL NOTE * * * Only of late years have the manuscripts of Leonardo da Vinci seen the light and the many difficulties been overcome which long proved an obstacle to their publication. The labour of editing, deciphering and translating his many scattered and fragmentary codices was beyond the efforts of any single man. The gratitude of the cultivated world is therefore due to those who, like J. P. Richter, C. Kavaisson-Mollien, Luca Beltrami, Piumati, Sabachnikoff, and, last but not least, the scholars of the Academia del Lincei, have so faithfully devoted themselves to this task, which alone has made possible the present little work. It was unavoidable that the form in which these manuscripts have been published should practically restrict their possession to the great libraries. But an excellent volume of selections from the writings of Leonardo, which are found in so haphazard a manner scattered through his codices and intermingled with his drawings and diagrams, has been published in Italy (Leonardo da Vinci: Frammenti Letterari e Storici, Florence, 1900). By kind permission of its editor, Dr. Solmi, this has served as a basis for the text of the present translation. The references, however, have {194} been verified with the complete editions of Leonardo's works, while a different arrangement has been made of the text. L. E. [Sidenote: Table of References] TABLE OF REFERENCES [A] Les manuscrits de Leonard de Vinci. Le manuscrit A de la Bibliotheque de l'Institut. Edit. Ravaisson-Mollien, vol. i. Paris, 1880. [ASH I] Les manuscrits de Leonard de Vinci. Les manuscrits H de la Bibliotheque de l'Institut; 2038 (Ash I) et 2037 (Ash II) de la Bibliotheque Nationale. Edit. Ravaisson-Mollien, vol. vi. Paris, 1891. [ASH II] Idem. [B] Les manuscrits de Leonard de Vinci. Les manuscrits B et D de la Bibliotheque de l'Institut. Edit. Ravaisson-Mollien, vol. ii. Paris, 1883. [C] Les manuscrits de Leonard de Vinci. Les manuscrits C, E et K de la Bibliotheque de l'Institut. Edit. Ravaisson-Mollien, vol. iii. Paris, 1888. [C A] Il Codice Atlantico di Leonardo da Vinci nella Biblioteca Ambrosiana di Milano. Rome; Milan, 1891. (Still in course of publication.) [D] See B.