nier, near Chambéry, on 23 December 1248; Uzielli Leonardo da Vinci e le Alpi. In the Bulletin of the Club Alpino Italiano, Year 1889, vol. XXIII, pg. 86. however is forced to admit that the “ruina” recalled by Leonardo happened as a result of the succession of earthquakes which occurred in many areas of northern Italy in the years 1504-1506, and therefore the period around which the considerations below lead us to suppose that the Codex might have been written. It would appear to me that these pages, or at least most of them, were written during one of Leonardo’s stays in Florence, excepting the period of his youth. Leonardo recalls that distant time, when he speaks of the “legniami delle travi lavorati, fatti già neri, li quali furon trovati a mio tempo in quel di Castel Fiorentino” [the timber of carved beams, already blackened, which were found during my time in Castel Fiorentino] (sheet 9v). The examples which illustrate Vinci’s theories draw frequently from hydrographic and stratigraphic conditions in Tuscany and, although they are found mixed up with others referring to northern Italy, they may generally be distinguished on account of the precise and up to date observations lacking in the latter; It may be said that the sketch and indications on sheet 32 r. relative to a “scala di Vigevine, sotto la Sforzes[c] a” (the Vigevine steps, below the Sforzesca) set up so as to regulate and decrease the flow of water, constitute exceptions to such poverty of detail (as far as Lombardy is concerned). But a note in the H manuscript, sheet 65 [17] v., shows how Leonardo may have conjectured such information and the sketch (lacking in effect any special characteristics) from previous notes, if not from memory, having taken himself precise measurements regarding steps of this scale at the Sforzesca during 1494, and perhaps even on other occasions. In addition it may be observed that if the other similar but more rapid mention on sheet 21 r. refers to the same steps (as is probable, despite the difference in the overall height here mentioned, and that resulting from sheet 32 r., when one adds up the height of the steps: a difference which would also be explained by observation having been made much earlier)…( forse manca qualcosa) and this appears to be true even when in the Codex there are not just observations but figures copied from other notebooks of the genius. The discovery of a prehistoric ship on the property of Messer Gualtieri, Sheet 9 v. The person mentioned here is, with every probability, Gualtiero da Bescapé, a relative of Lodovico il Moro, often commissioned by the latter to supervise the execution of artistic commissions; he thus found himself in frequent contact with Leonardo. near Candia Lomellina; the phenomena which the formation of an immense cloud gave rise to, which Leonardo could see “già sopra a Milano, inverso lago Maggiore”(already above Milan, in the opposite direction to Lake Maggiore; Sheet 28 r. the trip to Monte Rosa, Sheet 4 r.; 36 r. While perhaps merely a case of chance coincidence, it is worth noting that many of the reminiscences regarding northern Italy refer to places situated on the other side of the Ticino. As well as Vigevano, Candia Lomellina, and Monte Rosa, Leonardo recalls Monferrato (8 v., 10 v.) and Alessandria della Paglia (10 v.); as if pulled in that direction by the memory of the latter events of his time spent in the service of Lodovico il Moro. In the pocket book, L, containing some memories of the last years of the XV century (cf. the note dated 1497 on sheet 94 r.,) and which Leonardo took around with him at the beginning of the XVI century, we find (sheet 1 recto), with some other notes, the following: “to Casale Gienovese” (if this is, as it seems to be, the meaning of the fragment, interpreted differently by Ravaisson-Mollien); to which should be added perhaps another fleeting mention on the verso of the cover sheet: “co di Ronco” [Ronco’s house]; perhaps also: “Marcello sta in casa d’Iacomo da Mongiardino”[Marcello is at Iacomo’s house in Mongardino] or “da Mongardino”[at Mongiardino’s] (ms. L, recto of the cover sheet; here too suggesting a correction to Ravaisson-Mollien). It seems probable that Sforza availed of Leonardo sooner or later, in the defence preparations against the feared French invasion, danger of which had already been imminent at the beginning of 1497, when his lands in Liguria had been attacked and threatened from the side of Alessandria (cf. the Chronicles of Giovan Pietro Cagnola in Volume III of the Italian Historic Archive, Florence, Vieusseux, 1842, pg. 210-213); for the visit made by Lodovico with his followers to Genoa in 1498, taking the opportunity to give orders regarding strongholds and the defence of the state, cf. Pelissier (Léon G.) Documents pour l’histoire de l’établissement de la domination française à Gênes, in records of the Ligurian Historical Society, Genoa, 1894, pg. 337 and following. which provided Leonardo with a demonstration of the cause of the blue in the sky are but vivid memories of the past. The Po Valley, the Lombard lakes and rivers, the Martesana Canal Sheet 18 r. and the Grand Canal ibid. are mentioned without minute detail in the course of the considerations contained in this manuscript. Nor are there many notes on the fossils of Lombardy or on the parts of the Po Valley occupied by the sea in ancient times. But when Leonardo speaks of Tuscany, in a bold and enlightened explanation of his geological theory, he gives a detailed description of the changes taking place in the Arno valley Sheet 8 v.; 9 r. with accurate indications of the places and fresh impressions of that area familiar to him containing the villages of Vinci, He probably went back to Vinci more than once after 1500. Several notes, here and there in the Atlantic Codex (sheet 247 r.-a; 282 r.-b; 346 r.-c, cf. W. L. 212 r., in Richter, op. cit, II, § 1437, pg. 432), speak of these return trips to his birthplace, of the cares and interest that Leonardo still had there. The mention in the unusual journey plan, secretly hinted at on sheet 247 r.-a of the Atlantic Codex, shows that Leonardo considered (at a time which was most probably around 1499-1500) Vinci a safe haven, where he could have stopped off and left some of his furnishings; and where he might well have left, in the still uncertain times of his return to Florence or during his subsequent trips after 1500, not just some clothes and blankets but even some of his books. We refer here and below (pg.21) to the possibility that the Leicester manuscript may have remained in Tuscany, perhaps in Vinci, when Leonardo went – towards the middle of 1506 – to Milan, having obtained a three month pass from the Seignory of Florence (cf. Milanesi, in the notes to the Sansoni edition of Vasari’s Lives, IV, Firenze, 1879, pg. 44), which had to be extended to about halfway through August 1507: a rather vague and uncertain hypothesis, especially if one calls to mind the quarrel which soon occurred between Leonardo and his brothers, but which may however be accepted as possible, just as the doubt that some pages of the codex may have been written in his native region, which a significant number of observations refer to. In one point of the manuscript, where Leonardo begins to speak of the sequence of fluvial materials, and before the big stones, which are found in the shingly soil of the “fiume, che esce de’ monti” [river, coming out of the mountains] (sheet 6 v.), he begins to write “Il fiume Vin” [the Vin river], but soon, interrupts himself and crossing out the name, left half written, of the obscure Vincio, which descends in bounds amid his native slopes, explaining a local observation in a generalised form.