Geology

Geology

In the later years of his life Leonardo da Vinci described the configuration of the earth’s crust as the result of actual processes, principally fluvial, operating over immense periods of time—a system of geology which Duhem described as “perhaps his most complete and lasting invention” (Duhem, II, p.342).

For Leonardo , the study of the great world was related to the study of man. “Man is the model of the world” (Codex Arundel, fol. 156v; De Lorenzo, p.8), he wrote, “-called by the ancients a microcosm..., composed like the earth itself, of earth, water, air and fire; as man contains within himself bones, the supports and armature of the flesh, the world has rocks, the supports of the earth’s; as man has in him the lake of blood which the lungs swell and decrease in breathing, the body of the earth has its oceanic sea which also swells and diminishes every six hours in nourishing the world” (MS A fol. 55v).

Leonardo’s geologic perceptions date back to his earliest apprenticeship in Florence. Horizontally stratified rocks in the foreground and pyramidal peaks above a background sea in the Baptism of Christ (Uffizi, Florence), which he worked on with his master Verrocchio in 1472, reflect the influence of Van Eyck on Florentine landscape conventions (Castelfranco, p. 472).

Leonardo’s earliest dated work (1473), probably drawn in the field, is a sketch of the valley of the Arno (Uffizi). It displays similar characteristics-horizontal strata with waterfalls in the right fore ground, and eroded hills above a broad alluvial valley behind.

In subsequent drawings and paintings, rocks may be thrown into cataclysmic contortions but at the same time are folded and fractured realistically. (Leonardo’s infrequent mentions of earthquakes [Codex Leicester, fol. 10v], volcanoes [codex Arundel, fol. 155r; and Richter, 1939], and internal heat betray a lack of firsthand familiarity with Italy from Naples south. His idea of catastrophe was of storm, avalanche, and flood, and his apocalyptic essays do not alter the essential actualism of his system. He pointedly neglects the plutonist orogenic ideas of Albertus Magnus for the gradualist-neptunism of Albert of Saxony [Duhem, II, p.334].) The cliffs rising from a harbor in the background to the Annuciation (Uffizi) are not unlike views from above Lake Como or Lake Maggiore in the gathering mists. But the ultimate expression of Leonardo’s visual apprehension of topography and the true measure of the extent of his journey from the first sketch of 1473 is in the Windsor drawings of the Alps above the plains of the Po (Windsor Collection, folios 12410, 12414). They were done in the final years of his life in Italy at about the same time that he formulated his geologic notes in Tuscany before his Alpine studies). In these notes Leonardo boldly rejected Judeo-christian cosmology for the secular naturalism of the classical tradition as demonstrated by natural processes and by the actual configuration of the material world. Leonardo estimated that 200,000 years were required for the Po to lay down its plain ([Muentz, p.34]; he had clearly abandoned the JudeoChristian time scale for one that was two to three orders of magnitude greater [cf. Duhem, II, p. 335; and Richter, p. 915]).

In Leonardo’s system, the highest peaks of the Alps and the Apennines were former islands in an ancient sea. Mountains are continually eroded by winds and rains. Every valley is carved by its river, which is proven by the concordance of the stratigraphic column across the valley walls (codex Leicester, fol. 10r) and the proportionality of river size to valley breadth (Codex Atlanticus fol. 321b). The foothills and plains made by alluvial deposition continually extend the area of land at the expense of the sea. Mountains made lighter by erosion rise slowly to maintain the earth’s center of gravity at the center of the universe, bringing up petrified marine strata with their accompanying fauna and flora to be eroded into mountains in their turn.

Such great lakes as the Black Sea are impounded by the collapse of mountains and then, as streams breach the barriers, they drain down one into the other. In this way the Arno was seen to be cutting through its own flood plain, the Po to have filled in the great north Italian triangle from the Alps and Apennines to Venice, and the Nile from Memphis to Alexandria. The Mediterranean itself, the “greatest of rivers,” is being filling by the expanding deltas of its tributaries. When the future extension of the Nile erodes through the barrier of the Pillars of Hercules, it will drain what remains of the Mediterranean. Its bottom, relieved of the weight of the superincumbent sea, will rise isotatically (not to be confused with the modern concept of isotasy) to become the summits of mountains.

Just as Leonardo turned to dissection to study anatomy, so he dissected the earth—first in Milan during the years that he spent with Ludovico Sforza (il Moro); later as architect and engineer-general to Cesare Borgia and in land reclamation in Tuscany and for Leo X—for a period of 33 years from 1482 until 1515. Excavations for canals, moats, and roadways in Lombardy, Tuscany, Emilia, and the Romagna were carried out under his direct supervision during most of his career. He constructed plans and relief maps requiring exact measurements as well as lithologic and structural insight. His designs for surveying and drafting instruments; his numerous sketches, notes, and calculations of costs, manpower, and time; and his meticulous plans of machines for excavation and hydraulic controls all attest to the extent of his occupation with practical geology. The maps themselves- “bird’s—eye” topographic constructions, releif maps, and outline plans of drainage and culture are the geological analogues of his anatomical drawings, transcending sixteenth—century technics and science.

Leonardo was familiar with classical geological traditions through the works of Albertus Magnus and Cecco d’Ascoli, Vincent of Beatuvias, Ramon Lull, Isidore of Seville, Jan de Mandeville, and, above all, Albert of Saxony. Yet his demonstrations of the organic origins of fossils in situ, the impossibility of the biblical deluge, and the natural processes of petrifaction are based on meticulous observations—for example, of growth lines on shells (Codex Leicester, fol. 10a; Richter, p,990).

“When I was casting the great horse at Milan...,” he wrote, “Some countrymen brought to my workshop a great sack cockles and corals that were found in the mountains of Parma and Piacenza” (Codex leicester, fol. 9v). Was it his experience with the process of casting that led him ultimately to discuss the origins of the fossils and their cssts; of worm tracks;glossopetrae; fragmented and complete shells; paired and single shells; leaves; tufa; and conglomerates? Did this casting experience lead to a discussion of the relationship of velocity of flow to the sedimentary gradation from the mountains to the sea, of coarse gravels and breccias to the finest white potter’s clay?

Leonardo also observed and discussed turbidity currents (Codex Leicester, fol. 20r); initial horizontality (MS F, fol 11v); the relationship of sedimentary textures to turbulence of flow, graded bedding, the formation of evaporites of folded stara with mountains (Codex Arundel, fol.30b, Richter, 982).After numerous false starts, he arrived at an understanding of the hydrologic cycle (MS E, fol. 12a and Richter, 930); he dismissed the Pythagorean identification of the forms of the elements with the Platonic solids (MS F and Richter, 939); and he recorded the migration of sand dunes (MS F, fol. 61a and Richter, 1087).

After the period as engineer with Cesare Borgia, Leonardo had returned to Florence, then proceeded to Rome, and finally found sanctuary in Milan in 1508. Here he made the geologic notes of MS F under the heading De mondo ed acque. it is from this period also that the red chalk Windsor drawings of the Alps date, reflecting his interest in, and excursions into, the nearby Alps (Clark, p.134).

Leonardo brought not only his experience and his scientific principles to his landscapes, but also his sense of fantasy (Castelfranco, p. 473). The foreground of the two versions of the Virgin of the Rocks (Louvre and National Gallery) appears to be alternately horizontal, vertical, and horizontal strata, with caves widening into tunnels so that the roofs form natural bridges, some of them falling in. Such hollowing out from underneath and falling in of the back is the same mechanism used by Nicholas Steno in his Prodromus of 1669 to account for the inclination of strata.

Duhem has argued cognetly that Leonardo’s ideas were transmitted through Cardano and palissy to the modern world. There are many similarities which suggest a connection also with the highly influential Telliamed of Benoit de Maillet (1749). The notebooks were in part accessible well in advance of the modern development of a natural geology. G.B. Venturi’s studies of the geologic material in the notebooks were published in 1797 when catastrophic views of earth history were dominant. This was the year of birth of Charles Lyell, whose Principles of Geology in 1830 first formally established actualism as geologic orthodoxy. ( In later editions of the Principles, Lyell wrote that his attention was called to the Venturi studies by H.Hallam. G. Libri’s notes on Leonardo’s geology also date to the decade of Lyell’s principles. By contrast, the diluvial doctrine which Leonardo had demolished was seriously defended by William Buckland in his Reliquiae diluviianae as late as 1823, and catastrophism persisted well into the second half of the nineteenth century.)

Unfortunately, Leonardo rarely if ever sketched an indubitable fossil. He discussed but never illustrated the vivid Lake Garda ammonitico rosso —a Jurassic red marble with striking spiral ammonites used extensively in Milan. Leonardo’s realistic strata, especially in the Virgin and St.Anne of the Louvre, closely resemble these limestones as they weather in the Milanese damp. How is it possible that his “ineffable left hand” traced no illustrations of his comments—those comments which in their freshness, their simplicity, and vivid detail are a warranty of firsthand observation and an actualistic geologic position not achieved again for centuries? “The understanding of times past and of the site of the world is the ornament and the food of the human mind,” he wrote (Codex Atlantieus, fol. 365v).

Cecil J. Schneer

BIBLIOGRAPHY

Arbitrary Collections
1. Codex Atlanticus	1478–1518
2. Windsor Collection	1478–1518
3. Codex Arundel	1480–1518
Notebooks
4. Codex Forster, I2 (fols. 41–55)	1480–1490
5. MS B	ca.1489
6. Codex Trivulzianus	ca. 1489
7. MS C	1490
8. Codex Madrid, II(fols. 141–157)	1491–1493
9. MS A	1492
10. Codex Madrid, I	1492–1497
11. Codex Forster, II1,II2,III	1493–1495
12. MS H	1493–1494
13. MS M	ca. 1495
14. MS I	1495–1494
15. MS L	1497; 1502–1503
16. Codex Madrid, II (fols. 1–140)	1503–1505
17. MS K 1	1504
18. MS K 2	1504–1509
19. Codex Forster, I1	1505
20. Codex on Flight...	1505
21. Codex Leicester	ca. 1506
22. MS D	ca.1508
23. MS F	1508–1509
24. MS K 3	1509–1512
25. Anatomical Folio A	ca. 1510
26. MS G	1510–1516
27. MS E	1513–1514

Note : Not all scholars are in agreement as to the years given above. It is, however, a matter of plus or minus one or two years.

I. Original Works. Published treatises (compilations) are Treatise on Painting (abr.), pub. by Rafaelle du Fresne (Paris, 1651), complete treatise, as found in Codex Urbinas latinus 1270, trans. into English, annotated, and published in facs. by Philip A. McMahon (princeton, 1956); and Il trattato del moto e misura dell acqua..., pub. from Codex Barberinianus by E. Carusi and A. Favoro (Bologna, 1923).

Published MSS are Codex Atlanticus, facs. ed. (Milan, 1872 [inc.], 1894–1904), consisting of 401 fols., each containing one or more MS sheets (Codex is in the Biblioteca Ambrosiana, Milan); MSS A—M and Ashburnharn 2038 and 2037 (in the library of the Institut de France), 6 Vols., Charles Ravaisson-Mollien, ed. (Paris, 1881–1891), consisting of 2,178 facs. reproducing the 14 MSS in the Institut de France and Bibliotheque Nationale, with transcription and French trans.; Codex Trivulzianus, transcription and annotation by Luca Beltrami (Milan, 1891), containing 55 fols.; Codex on the Flight of Birds, 14 fols. by Theodore Sabachnikoff, transcribed by Giovanni Piumati, translated by C. Ravaisson-Mollien (Paris, 1893, 1946); The Drawings of Leonardo da Vinci at Windsor Castle, cataloged by Kenneth Clark, 2nd ed., rev. with the assistance of Carlo Pedretti (London, 1968), containing 234 fols.: repros. of all the drawings at Windsor, including the anatomical drawings (notes are not transcribed or translated where this has been done in other works such as the selections of J. P. Richter, Anatomical Folios A and B, and the Quaderni d’anatomia; see below); Dell’anatomia Fogli A, Pub. by T. Sabachnikoff and G. Piumati (Turin, 1901); Dell’anatomia fogli B, pub. by T. Sabachnikoff and G. Piumati (Turin, 1901); Quaderni d’anatomia, 6 vols., Ove C. L. Vangensten, A. Fonahn, and H. Hopstock, eds. (Christiania, 1911–1916), all the anatomical drawings not included in Folios A and B; Codex Leicester (Milan, 1909), 36 fols., pub. by G. Calvi with the title Libro originale della natura peso e moto Belle acque (Codex is in the Leicester Library, Holkham Hall, Norfolk); Codex Arundel, a bound vol. marked Arundel 263, pub. by the Reale Commissione Vinciana, with transcription (Rome, 1923–1930), containing 283 fols. (Codex is in British Museum); and Codex Forster, 5 vols., 304 fols., pub. with transcription by the Reale Commissione Vinciana (Rome, 1936) (Codex is in the Victoria and Albert Museum, London).

MSS are J. P. Richter, The Literary Works of Leonardo da Vinci, 2 vols. (London, 1970), containing a transcription and English translation of a wide range of Leonardo’s notes used as a reference work in Clark’s Catalogue of the Drawings at Windsor Castle; and E. MacCurdy, The Notebooks of Leonardo do Vinci, 2 vols. (London, 1939; 2nd ed., 1956), the most extensive selection of Leonardo’s notes.

II. Secondary Literature. The following works can be used to obtain a general picture of Leonardo’s scientific work: Mario Baratta, Leonardo do Vinci ed i problenn delta terra (Turin, 1903); Elmer Belt, Leonardo the Anatomist (Lawrence, Kan., 1955); Girolamo Calvi, I manoscritti di Leonardo da Vinci (Rome, 1925); B. Dibner, manoscritti di Vinci, Military Engineer (New York, 1946), and Leonardo da Vinci, Prophet of Automation (New York, 1969); Pierre Duhem, Etudes sur Leonard de Vinci (Paris, 1906–1913; repr. 1955); Sigrid Esche-Branunfels, Leonardo da Vinci, das anatomische Werk (Basel, 1954); Giuseppe Favoro, Leonardo da Vinci, i medici e la medicina (Rome, 1923), and “Leonardo da Vinci e l’anatomia,” in Scientia, no. 6 (1952), 170–175; Bertrand Gille, The Renaissance Engineers (London, 1966); I. B. Hart, The World of Leonardo da Vinci (London, 1961); L. H. Heydenreich, Leonardo da Vinci (Berlin, 1944), also trans. into English (London, 1954); K. D. Keele, Leonardo da Vinci on the Movement of the Heart and Blood (London, 1952); “The Genesis of Mona Lisa,” in Journal of the History of Medicine, 14 (1959), 135; and “Leonardo da Vinci’s Physiology of the Senses,” In C. D. O’Malley, ed., Leonardo’s Legacy (BerKeley–Los Angeles, 1969); E. Mac Curdy, The mind of Leonardo da Vinci (New York, 1928); J.P.McMurrich, Leonardo da Vinci, the Anatomist (Baltimore, 1930); Roberto Marcolongo, Studi Vinciani; Memorie Sulla geometrai e la meccanica di Leonardo da Vinci (Naples, 1937); and A. Marinoni, “The Manuscripts of Leonardo da Vinci and Their Editions,” in Leonardo Saggie e ricerche (Rome, 1954).

See also C. D. O’malley, ed., Leonardo’s Legacy—an International Symposium (Berkeley—Los Angeles, 1969); C.D.O’Malley and J. B. de C. M. Saunders, Leonardo da Vinci on the Human Body (New York, 1952); Erwin Panofsky, The Codex Huygens and Leonardo da Vinci’s Art Theory (London 1940); A. Pazzini, ed.,Leonardo da Vinci. II tratto della anatomia (Rome, 1962); Carlo Prdretti, Documenti e memorie riguardanti Leonardo da Vinci a Bologna e in Emilia (Bologna, 1953); Studi vinciani (Geneva, 1957); andLeonardo da Vinci on Painting—a Lost Book (Libro A) (london, 1965); Raccoltavinciana, “Commune di Milano, Castello Sforzesco,” I–XX (Milan, 1905–1964); ladislao Reti, “Learti chimiche di Leonardo da Vinci,” in Chimica e l’industria, 34 (1952), 655–721; “Leonardo da Vinci’s Experiments on Combustion,” in Journal of Chemical Education, 29 (1952), 590; “The Problem of Prime Movers,” in Leonardo da Vinci, Technologist (New York, 1969); and “The Two Unpublished Manuscripts of Leonoardo da Vinci in Madrid,” ibid., I.A.Richter, Selections From the Notebooks of Leonardo da Vinci (Oxford, 1962); Vasco Ronchi, “Leonardo e L’ottica,” in Leonardo saggi e richeche (Rome, 1954); George Sarton, Leonardo de Vinci, ingenieur et savant, Colloques internationaux (Paris, 1953), pp. 11–22; E.Solmi, Scritti vinciani, papers collected by Arrigo Solmi (Florence, 1924); K.T. Steintz, Leonardo da Vinci’s Tratto della pittura (Copenhagen, 1958); Giorgio Vasari,Lives of the Painters and Architects (London, 1927); and V.P.Zubov, Leonardo da Vinci, trans from the Russian by David H. Kraus (Cambridge, Mass, 1968).

The remainder of the bibliography is divided into sections corresponding to those in the text: Technology, Mechanics, Mathematics, and Geology.

Technology. On Leonardo’s work in technology, the following should be consulted: T. Beck,Beitrage zur Geschichte des Maschinenbaues, 2nd ed. (Berlin, 1900), completed in Zeitschrift des Vereines deutscher Ingenieure (1906), 524–531, 562–569, 645–651,777–784; I. Calvi, L’architettura militare di Leonardo da Vinci (Milan, 1943); G. Canestrini, Leonardo costruttore di machine e veicoli (Milan, 1939); B. Dibner, Leonardo da Vinci, Military Engineer (New York, 1946); F.M. Feldhaus, Leonardo der Techniker und Erfinder (Jena, 1922); R. Giacomelli, Gli scritti di Leonardo da Vinci sul volo (Rome, 1936); C. H. Gibbs Smith, “The Flying Machine of Leonardo da Vinci,” in shell Aviation News, no. 194 (1954); The Aeroplane (London, 1960); and Leonardo da Vinci’s Aeronautics (London, 1967); B. Gille , Engineers of the Renaissance (Cambridge, Mass., 1966); I. B. Hart, The Mechanical Investigations of Leonardo da Vinci (London, 1925; 2nd ed., with a foreword by E. A. Moody, Berkeley—Los Angeles, 1963), and The World of Leonardo da Vinci (London, 1961); Leonard de Vinci et L’experience sceintifique au XVI Seicle (Paris, 1952), a collection of articles originally pub. in 1939; R. Marcolongo, Leonardo da Vinci artisa—scienziato c(Milan, 1939); W.B. Parsons, Engineers and Engineering in the Renaissance (Baltimore, 1939; 2nd ed., Cambridge, Mass., 1968); L. Reti, “Leonardo da Vinci nella storia della macchina a vapore,” in Rivista di ingegneria (1956–1957); L. Reti and B. Dibner, Leonardo da Vinci, Technologist (New York, 1969); G. Strobino, Leonardo da Vinci e la meccanica tessile (Milan, 1953); C. Truesdell, Essays in the History of Mechanics (New York, 1968); L.Tursini, Le armi di Leonardo da Vinci (Milan, 1952); A. Uccelli, Storia della tecnica... (Milan, 1945), and I libri del volvo di Leonardo da Vinci (Milan, 1952); A.P. Usher, A History of Mechanical Inventions, rev.ed. (Cambridge, Mass., 1954); and V.P. Zubov, Leonardo da Vinci (Cambridge, Mass., 1968).

Mechanics Particularly useful as a source collection of pertinent passages on mechanics in the notebooks is A. Uccelli, ed,I libri di meccanica... (Milan, 1942). The Pioneer analytic works were those of P.Duhem, Les origines de la statique, 2 vols. (Paris, 1905–1906), and Etudes sur Leonard de Vinci (Paris, 1906–1913; repr. 1955). These works were the first to put Leonardo’s mechanical works into historical perspective. Their main defect is that a full corpus of Leonardo’s notebooks was not available to Duhem. They are less successful in interpreting Leonardo’s dynamics. Far less perceptive than Duhem’s work is F.Schuster’s treatment of Leonardo’s statics, Zur Mechanik Leonardo da Vincis (Erlangen, 1915), which also suffered because the sources available to him were deficient. A work that ordinarily follows Schuster (and Duhem) is I. B. Hart, The Mechanical Investigations of Leonardo da Vinci (London, 1925; 2nd ed., with foreword by E.A. Moody, Brekeley- Los Angeles, 1963). It tends to treat Leonardo in isolation, although the 2nd ed., makes some effort to rectify this deficiency. The best treatment of Leonaardo’s mechanics remains R. Marcolongo, Studi vinciani: Memorie sulla geomatria e la meccanica di leonardo da Vinci (Naples, 1937). It is wanting only in its treatment of Leonardo’s hydrostatics and the motion of fluids. For a brief but important study of Leonardo’s hydrostatics, see F. Arredi,Le origini dell’idrostatica (Rome, 1943), pp.8–16. For an acute appraisal of Leonardo’s mechanics in general and his fluid mechanics in particular, see C. truesdell,Essays in the History of Mechanics (New York, 1968), pp. 1–83, esp, 62–79. Finally, for the influence of Archimedes on Leonardo, see M. Clkagett, “Leonardo da Vinci and the Medieval Archimedes,” in Physics, 11 (1969), 100–151, esp. 108. 108–113, 119–140.

Mathematics The most thorough study of Leonardo’s mathematical works was carried out in the first part of the twentieth century by R. marcolongo, whose most important writings are: “Le ricerche geometrico—meccaniche di Leonardo da Vinci,” in Atti della Societa italiana delle scienze, detta dei XL, 3rd ser., 23 (1929), 49–100; II trattato di Leonardo da Vinci sulle trasformazioni dei solidi (Naples, 1934); and Leonardo da Vinci artista–scienziato (Milan, 1939). The cited article of C. Caversazzi, “Un’invenzione geometrica di Leonardo da Vinci,” is in Emporium (May 1939), 317–323. Important article sare M. Clagett, “Leonardo da Vinci and the Medieval archimedes,” in Physis, II (1969), 100–151; and C. Pedretti, “The Geometrical Studies,” in K. Clark, The Drawings of Leonardo da Vinci at Windsor Castle, 2nd ed., rev. (London, 1968), I, xlix–liii; and “Leonardo da Vinci: Manuscripts and Drawings of the French Period, 1517–1518,” in Gazette des beauxarts (Nov. 1970), 185–318.

The following studies by A. Marinoni provide a detailed analysis of some of Leonardo’s works: “Le operazioni aritmetiche nei manoscritti vinciani,” in Raccolta vinciana, XIX (Milan, 1962), 1–62; “La teoria dei numeri frazionari nei manoscritti vinciani. Leonardo e Luca Pacioli,” ibid., XX (Milan, 1964), 111–196; and “L’ aritmetica di Leonardo,” in Periodico di matematiche (Dec. 1968), 543–558. See also Marinoni’s L’essere del nulla (Florence, 1970) on the definitions of the “principles” of geometry in Leonardo, and “Leonardo da Vinci,” in Grande antologia filosofica (Milan, 1964), VI, 1149–1212, on the supposed definition of the principle of inertia.

Geolgy. On Leonardo’s work in geology, see the following: Mario Baratta, Leonardo da Vinci ed i Problemi della terra (Turin, 1903); I disegni geografici di Leonardo da Vinci conservati nel Castello di windsor (Rome, 1941); Girolamo Calvi, Introduction, Codex Leicester (Rome, 1909); Giorgio Castelfranco, “Sul pensiero geologico eil paesaggio di Leonardo,” in Achille Marazza, ed., Saggi e Ricerche (Rome, 1954), app. 2; Kenneth Clark, Leonardo da Vinci (Baltimore, 1963) Giuseppe De Lorenzo, Leonardo da Vinci e la geologia (Bologna, 1920); Pierre Duhem, Etudes sur Leonard de Vinci, 3 vols. (Paris, 1906–1913; repr. 1955); Eugene Muentz, Leonardo da Vinci, Artist, Thinker, and Man of Science (New York, 1898); and J. P. Richter, ed.,The Notebooks of Leonardo da Vinci (New York, 1970).