indeed, in their chaotic confusion they are anything rather than
satisfactory reading. The fault, no doubt, rests with the compiler
of the Vatican copy, which would seem to be the source whence all
the published and extensively known texts were derived; for, instead
of arranging the passages himself, he was satisfied with recording a
suggestion for a final arrangement of them into eight distinct
parts, without attempting to carry out his scheme. Under the
mistaken idea that this plan of distribution might be that, not of
the compiler, but of Leonardo himself, the various editors, down to
the present day, have very injudiciously continued to adopt this
order--or rather disorder.

I, like other enquirers, had given up the original Manuscript of the
Trattato della Pittura for lost, till, in the beginning of 1880, I
was enabled, by the liberality of Lord Ashburnham, to inspect his
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