Leonardo da Vinci’s mental and calligraphic energy overflowed into innumerable notebooks; “innumerable” because, although a daunting collection of these notebooks has come down to us, we shall never know how many there were originally. To give three indications of how much is lost: Francesco Melzi, his devoted disciple and heir, transcribed most accurately observations on the art of painting which were scattered throughout the notebooks in order to compile a more or less coherent treatise on the subject, later to be published as the Trattato della Pittura. Of these extracts only about a quarter can still be read in Leonardo’s hand; three quarters were in notebooks now lost.

Melzi’s son, no doubt in reaction against his father’s hero worship, took so little interest in Leonardo that he allowed an enterprising tutor to remove thirteen of the notebooks and try to sell them to the Duke of Florence. When he failed the conscience-stricken tutor offered to return them, but Orazio Melzi said that he was not interested. At this point Leonardo’s MSS and drawings were saved by the admirable sculptor, Pompeo Leoni, who took them with him to Spain, and set about cataloguing and arranging them. He numbered the notebooks from one to forty-six: of these only nineteen have survived. Finally we may observe that, in the list of books which is one of the most fascinating items in the recently discovered Madrid notebooks, Leonardo mentions fifty large and small books, which were apparently contained in his own writings. So the surviving remains of Leonardo’s notes and calculations, which Heaven knows are voluminous enough, are only a fraction of what he bequeathed to Melzi.

This need not arouse the kind of lamentation that is caused by the lost books of Livy or the poems of Sappho. The greater part of Leonardo’s notebooks are remarkably uninteresting in themselves. He was a compulsive notetaker. He would draw and describe anything that he saw, even when he had done so before several times. He was fascinated by mathematics and geometry, and would fill many pages with calculations which are of no interest to mathematicians, and of even less interest to the art historian. He loved to record how things worked, and when his subject is the human body we are interested. But when it is some rather elementary machinery, we are not. The majority of Leonardo’s notebooks are strictly specialist material.

Of course there are exceptions. The vast collection of loose sheets formerly pasted into a volume known as the Codex Atlanticus, and now rearranged in seven volumes, contains many magnificent drawings of machinery and architecture. The notebooks known as MS B in the Bibliothèque de l’Institut are almost our only sources for Leonardo’s ideas on architecture and town planning, and contain in addition some spirited studies of figures in action and exquisite drawings of flowers. One of the small pocket books in the Victoria and Albert Museum contains some ravishing little drawings, and some precious indications of what was passing through his mind while he was planning the Last Supper.

But the serious student cannot afford to skip a single page of the notebooks, because Leonardo had a habit of adding to a page of geometrical calculations or observations of the movement of water a dated note about his own movements, a reminder of someone he had met or even the name of a place; and it is from these clues that our knowledge of his life is being continually enlarged. True, one gradually develops a sixth sense of where such interpolations will occur (often on the first and last pages) and what they will look like (usually isolated or written a traverso). But nothing takes the place of a long slog, and it is an exacting process. At least two eminent Leonardists have gone mad, and several of the others have shown uncomfortable signs of nervous tension. He is too heavy and weighty for any scholar to bear.

In 1965 the world of art scholarship was amazed to read a report that two unknown MSS by Leonardo had been discovered in the National Library of Spain in Madrid. The circumstances of this discovery have never been fully described and are passed over in silence in the present official publication. Their earlier history is clear. They were among the books brought to Spain by Leoni. They passed into the library of a famous collector named Don Juan de Espina, who refused to sell them to the Earl of Arundel, because he was determined to bequeath his whole collection to the king. On his death they were transferred to the Royal Library, and in about 1830 they passed to the National Library, where they were correctly catalogued.

This catalogue entry was noticed in 1898 by Tammaro Marinis, but the books had been given different “call numbers,” and even he, the most tenacious of bibliographers, was not allowed to look for them. Had he done so he would certainly have found them, as one of the volumes actually had the name of Leonardo da Vinci on the spine. He was definitely told that they were lost, or perhaps exchanged for something more important. However, he always maintained in private that they must be somewhere in the library.


The story of the “discovery” as it was told to me at the time was that a young American student of early Spanish literature working in the library sent in an application form with a call number that produced one of the Leonardo codices. Although not a scholar of Leonardo, he saw what it was, and contrived to take microfilms of the pages, which he sent back to his university in America. There could be no question of their authenticity. From this point forward the episode became overlaid by layer upon layer of untruth. The Spanish librarians maintained that Codex Madrid I had been included unlabeled in an exhibition of scientific MSS in 1965, but this, if true, would make their position even more indefensible, for to exhibit an unknown Leonardo MS without drawing attention to it or inviting Leonardo scholars to inspect it is almost incredible.

Gradually, I suppose, the full implications of the event dawned on the authorities, and their state of mind could be made the subject of an interesting short story. Their dilemma was unenviable, but they still held the trump card; the MSS could not be published without their permission, and this they would not give unless credit for the discovery was given to the Keeper of MSS. This condition is loyally observed in the present publication. A full examination of the circumstances of the discovery took place in 1967 under the chairmanship of Dr. Kristeller; the findings were put into a sealed envelope and are not to be disclosed for thirty years.

In due course the Madrid authorities recognized that the codices must be inspected by some competent person, and invited Dr. Ladislao Reti. He was an expert on Leonardo’s studies of machinery, and had a good knowledge of Leonardo’s notebooks in general. He had no hesitation in saying that the two Madrid codices were authentic works of the highest importance. Several other Leonardo scholars visited Madrid, but when, after complicated negotiations, the final permission to publish the book was given, the editor chosen was still Dr. Reti.

He did the work in an austere and economical manner, which shows him to have been (he died in October, 1973, soon after the edition was completed) a scrupulous scholar as well as an expert on Leonardo’s machinery. His transcription of Leonardo’s texts seems to be uniformly accurate. His concordances and appendixes are excellent, especially that on the list of Leonardo’s books in Madrid II. But it is regrettable that he did not give a short description of the drawings of machinery which occur on practically every page of Codex Madrid I, because although many of them may be quite elementary pieces, to the lay eye their purpose is usually incomprehensible. Altogether his commentaries are rather too sparing: but they are extravagantly amplified in the large book which I shall discuss later.

For the production of the book no praise can be too high. To compare the plates in Madrid I with those treating of a similar subject, MSS A and H in the Institut de France in the old standard edition by Ravaisson Mollien, is to realize that, if sufficient care is taken, modern reproduction can be in an entirely different class from that of the nineteenth century. One soldiered on with those dismal old plates and strained one’s eyes; but one never had any notion of the freshness and sparkle with which Leonardo committed his observations to paper. Even the so-called facsimile of MS B, done in 1960, is (making all allowances for a rougher paper) far less clear and attractive to the eye. When the two codices were first discovered there was some competition among publishers for the right to publish them, and it was fortunate that the commission finally went to a firm strong enough to insist on reproductions of this high quality in spite of what must have been unthinkable expense.

As for the actual contents of the codices: Madrid I is the longest and most systematically arranged of all Leonardo’s notebooks, and contains the most illustrations. Unfortunately it is limited to the subject of machinery, and even experts of this branch of Leonardo’s studies find it difficult to maintain their enthusiasm throughout a series of over 300 pages. Many of the drawings are worked-up copies of sketches in other MS material, notably the Codex Atlanticus, Codex Forster, and MS H; and evidently Leonardo began with the intention of making this MS a final summary of his observations on machinery. He was later to plan, and perhaps executed, “final” collections on the subjects of anatomy and painting (the latter brilliantly reconstructed by Carlo Pedretti in his Libro A), but both of these are lost. However, this exceptional effort to achieve order does not go much further than the drawings of the machines.


These were always done first and are exceptionally neat and clear. Beside them was placed, with an unerring sense of design, a column of text which, however, is not always related to the function of the machine. But Leonardo, being what he was, could never resist afterthoughts, so that some of the sheets have lost their aesthetic quality without any gain in intellectual value. About three quarters of the way through the book Leonardo turns from practice to theory, and these pages are actually numbered backward from f. 190 to f. 158. These pages involve more questions than answers, particularly on the problem of gravity, which Leonardo knew was at the heart of all his problems, whether of engineering or of hydraulics, but for which he never could find an explanation that began to satisfy him.

How far are the machines illustrated Leonardo’s own inventions? The question is unanswerable because the craftsmen of the late Middle Ages kept their secrets to themselves and did not commit them to paper. But it is clear from references to German craftsmen, in particular Guilio Tedesco, that Leonardo looked to the north for technical innovation, and the character of the drawings in Madrid I suggests records of things seen rather than of inventions. It could be described as an illustrated guide to late medieval technology. To the layman its interest lies chiefly in the delicate precision of Leonardo’s drawings and in the evidence it provides that a man of such creative energy could be so patient.

Madrid Codex II is entirely different, and for the general student of Leonardo considerably more interesting. On the very first page is one of the best “shot-rang-out” openings in history.

Friday the 6th of June at the stroke of the 13th hour I started to paint in the Palace. As I lowered my brush the weather changed for the worse and the bell began to toll calling the men to the courtyard. The cartoon was torn, water poured down…. Suddenly the weather became even worse and it rained very heavily till nightfall. The day turned to night.

The passage, in addition to its dramatic quality, tells us two most interesting facts about Leonardo: the day and hour when he started the painting of the Battle of Anghiari in the Palazzo Vecchio, and that the cartoon was damaged by a storm.

Three pages later comes another rich haul for the Leonardist, a list of 116 books in Leonardo’s possession which he left in a chest in a monastery, probably when he went from Florence to Piombino in 1502. There is another list of forty of his books in the Codex Atlanticus. Scholars, like Solmi, have deduced from references in Leonardo’s MSS a large number of the books he had read and sometimes copied into his notebooks, but the Madrid list contains some real surprises. There are, for example, far more books of devotion and Christian philosophy than we could ever have inferred from his writings: works of S. Bernardino, St. Isidore, St. Ambrose, the sermons of St. Augustine—what had the “disciple of experience” to do with these? Dr. Reti has looked for the editions in which Leonardo is likely to have read and has discovered that the majority were translations into Italian; in spite of a lot of hard work, and the presence of several Latin grammar and word books on the list, Leonardo was never at ease with the Latin language, which can be the only reason (for he read prodigiously) why he could describe himself as a man without letters. After the list of books comes a list of clothes, including three garments in the French style that belonged to Salai—one of them given by Cesare Borgia.

In the next pages Leonardo addresses himself to the thankless task of diverting the River Arno as part of the Florentine campaign against Pisa. I used to think that this impossible undertaking was an example of Leonardo’s lack of realism, but it now seems that the plan was put forward by the archrealist Machiavelli, who persuaded Leonardo to attempt it. Leonardo’s text is concerned chiefly with the cost, but, fortunately for us, he also did ten landscape drawings, exquisitely delicate, and entirely naturalistic, which show that the landscape background of the Mona Lisa (probably painted at about the same time) was a construction of art.

A good deal of Madrid II will be of interest only to the specialist. In twenty-six pages he copies out extracts from a treatise on fortification by the Sienese architect Francesco di Giorgio; twenty-five pages are devoted to the subject of squaring the circle, an exercise that seemed important to Renaissance mathematicians, and had an obsessive interest for Leonardo. It was the principal subject in the edition of Archimedes by Pomponius Gauricus published in 1503.

On November 30, 1504, he writes a hasty, vivid scrawl: “Tonight I finally found the quadrature of the circle, as the light of the candle and the night and the paper on which I was writing were coming to an end.” The diagrams that support this statement are particularly unconvincing, and Leonardo seems to have returned to his problem next day.

Finally comes what is in effect a different MS, bound up with Madrid II for convenience, but written between 1491 and 1494. This is an account of Leonardo’s problems in casting the gigantic horse which was to be a monument to Francesco, founder of the House of Sforza. The monument was already in Leonardo’s mind when he wrote his original letter from Florence recommending himself to Ludovico, and was probably the chief reason for his entering Ludovico’s service. The horse was to be four times life size, and for some reason Leonardo determined to cast it all in one piece. Anyone familiar with Cellini’s account of the casting of the Perseus, a much smaller model, will remember the difficulties this method involves, which in Cellini’s case ended with panic.

No large equestrian statue was cast in one piece until Girardon’s Louis XIV, almost 200 years later, and it seems very doubtful whether Leonardo would have succeeded, even if his master’s fortunes had not declined and the bronze collected for the horse been sent to the Duke of Ferrara to be made into cannon. But his notes on the subject are among the most impressive examples of how Leonardo could apply his mind to a technical problem, and they end with a marvelous red chalk drawing for the protective casing of the mold of the horse’s head, which is visually the most striking thing to come out of the Madrid Codices. Incidentally, Dr. Reti, in his volume of commentary, simply refers to these pages as “notes on casting,” and does not mention the Sforza horse at all. I have no “inside knowledge,” but cannot help feeling that this extraordinary omission must be due to declining health, which might also account for a certain meagerness in his notes to the MSS to which I have already referred.

The McGraw-Hill Book Company, in undertaking this splendid and scrupulous publication of the two codices, must have realized that they would have only a limited appeal. They therefore decided to accompany their five aristocratic volumes of text and transcription with a large popular volume of exposition, which they have entitled The Unknown Leonardo. They invited ten eminent Leonardists to write on various aspects of his work which are illustrated or amplified by the Madrid Codices. In this way they intended to put the new discoveries into relation with Leonardo’s work as a whole, and make it more generally accessible.

The first impression of this book will alarm or distress the serious student, since the material is presented with all the devices of pictorial journalism. Plates overlap each other, paper changes color, enlarged details of drawings and unconvincing “portraits” of contemporaries fill the margins, and the texts of the ten scholars are often overwhelmed by the surrounding marginalia. A number of the color plates seem to be unnecessary and have been included only in order to promote a festive atmosphere in what would otherwise be a somewhat forbidding occasion.

But when one has accepted this kermesse héroïque atmosphere, the book turns out to have great merits and to have been conceived with considerable imagination. Among the color plates and “double spreads” are a few that any student of Leonardo will be glad to have, for example the beautiful plan of Imola, or the incredible opening in the Codex Atlanticus that contains 169 formulas for squaring a semicircle, with accompanying notes, and ends in pure pattern making, a sheet that seems more than any other to illustrate the almost insane industry with which Leonardo would concentrate on his obsessions. The marginal drawings are well annotated, and often make up for the lack of commentary in the severe presentation of the codices.

Inevitably, given the content of Madrid I, a majority of the scholarly articles are concerned with technique and mechanics. There is an admirable piece on the military architect by that stalwart Leonardist, Dr. Ludwig H. Heydenreich; there is an essay on horology which, to an ignoramus on this important topic, is fascinating. There are several articles on machines on which the art historian cannot pass judgment. There is even an extremely interesting article “Leonardo and Music.” Contemporary evidence leaves us in no doubt about his skill as a performer on the lira da braccio; the references to music in Leonardo’s MSS are spare and scattered, but they do contain the sublime definition, “figurazione delle cose invisibili.” As the visual arts play so little part in the Madrid Codices, it is to be expected that the articles on Leonardo as a painter and art theorist are less satisfying, and surely someone could have prevented a colored detail of the landscape of the Borghese Leda from appearing as an illustration to Professor André Chastel’s article.

To anyone interested in the whole phenomenon of Leonardo far the most interesting section of the book is that entitled “The Writer,” by Augusto Marinoni. The author has already shown himself the most perceptive and imaginative of all Leonardo scholars (with the possible exception of Zhubov, who had, unfortunately, no opportunity to study the drawings and MSS in the originals), and in this article he makes no concessions to the slightly euphoric spirit in which the rest of the book is composed. He not only recognizes that Leonardo, with his artisan-craftsman education, never mastered Latin, but also that “the preparation he had received in the field of mathematical sciences…was very inadequate. He was never very good at calculation, and even in terms of the knowledge of concepts the gaps in his education were far from insignificant.” Any fair-minded student of Leonardo will confirm this, and it is a tragedy that after the Battle of Anghiari he should have recorded his interest in life and movement no longer through drawings of life but through machines and mathematics.

“As he matured,” says Bern Dibner, the author of one of the articles in this volume, “the machine and its parts became the language of his involvement in the world.” This is too pessimistic. Leonardo was also driven on by two demons, the belief that the certainties could be stated only by mathematics, and the belief that every form of life could be stated in geometrical terms. This demoniacal possession owed its power to Leonardo’s intuition that both these propositions would ultimately be proved to be correct. And so they have. Modern science has stated almost all branches of knowledge, even biology, in mathematical terms; and high magnification has shown that the majority of organisms are made up of geometric particles. But Leonardo had not even a microscope. It took centuries before his inspired guesses were demonstrable, and so the attempts to prove his intuitive certainties ended in frustration, or, what was worse, in pointless mathematical games.

The reading of Leonardo’s original MSS, as opposed to edited extracts such as those of Richter or MacCurdy, is a depressing task. This marvelous brain, this inexhaustible energy, seems to be wasting itself three quarters of the time in futile exercises and innumerable repetitions. And yet one must labor on because every now and then a single sentence will reveal such an extraordinary intuition that one is left breathless. All the same, one may be allowed to wish that he had drawn more and written less.

This Issue

December 12, 1974