It is scarcely necessary to add that most of the drawings here reproduced in facsimile have never been published before. As I am now, on the termination of a work of several years' duration, in a position to review the general tenour of Leonardos writings, I may perhaps be permitted to add a word as to my own estimate of the value of their contents. I have already shown that it is due to nothing but a fortuitous succession of unfortunate circumstances, that we should not, long since, have known Leonardo, not merely as a Painter, but as an Author, a Philosopher, and a Naturalist. There can be no doubt that in more than one department his principles and discoveries were infinitely more in accord with the teachings of modern science, than with the views of his contemporaries. For this reason his extraordinary gifts and merits are far more likely to be appreciated in our own time than they could have been during the preceding centuries. He has been unjustly accused of having squandered his powers, by beginning a variety of studies and then, having hardly begun, throwing them aside. The truth is that the labours of three centuries have hardly sufficed for the elucidation of some of the problems which occupied his mighty mind.
Alexander von Humboldt has borne witness that "he was the first to start on the road towards the point where all the impressions of our senses converge in the idea of the Unity of Nature" Nay, yet more may be said. The very words which are inscribed on the monument of Alexander von Humboldt himself, at Berlin, are perhaps the most appropriate in which we can sum up our estimate of Leonardo's genius:
"Majestati naturae par ingenium."
LONDON, April 1883.
F. P. R.
CONTENTS OF VOLUME I.
PROLEGOMENA AND GENERAL INTRODUCTION TO THE BOOK ON PAINTING
Clavis Sigillorum and Index of Manuscripts.—The author's intention to publish his MSS. (1).—The preparation of the MSS. for publication (2).—Admonition to readers (3).—The disorder in the MSS. (4).—Suggestions for the arrangement of MSS. treating of particular subjects (5—8).—General introductions to the book on painting (9—13).—The plan of the book on painting (14—17).—The use of the book on painting (18).—Necessity of theoretical knowledge (19, 20).—The function of the eye (21—23).—Variability of the eye (24).—Focus of sight (25).—Differences of perception by one eye and by both eyes (26—29).—The comparative size of the image depends on the amount of light (30—39).