Manuscripts, and was so happy as to discover among them the original

text of the best-known portion of the Trattato in his magnificent

library at Ashburnham Place. Though this discovery was of a fragment

only--but a considerable fragment--inciting me to further search,

it gave the key to the mystery which had so long enveloped the first

origin of all the known copies of the Trattato. The extensive

researches I was subsequently enabled to prosecute, and the results

of which are combined in this work, were only rendered possible by

the unrestricted permission granted me to investigate all the

Manuscripts by Leonardo dispersed throughout Europe, and to

reproduce the highly important original sketches they contain, by

the process of "photogravure". Her Majesty the Queen graciously

accorded me special permission to copy for publication the

Manuscripts at the Royal Library at Windsor. The Commission Centrale

Administrative de l'Institut de France, Paris, gave me, in the most

liberal manner, in answer to an application from Sir Frederic

Leighton, P. R. A., Corresponding member of the Institut, free

permission to work for several months in their private collection at

deciphering the Manuscripts preserved there. The same favour which

Lord Ashburnham had already granted me was extended to me by the

Earl of Leicester, the Marchese Trivulsi, and the Curators of the

Ambrosian Library at Milan, by the Conte Manzoni at Rome and by

other private owners of Manuscripts of Leonardo's; as also by the

Directors of the Louvre at Paris; the Accademia at Venice; the

Uffizi at Florence; the Royal Library at Turin; and the British

Museum, and the South Kensington Museum. I am also greatly indebted

The Notebooks of Leonardo Da Vinci Complete