Collegonzi, Sheet 8 v. Capraia, Sheet 31 v. Monte Albano, Sheet 9 r.; 31 v. extending on the one side towards Val di Nievole, Sheet 9 r. and a short distance away, on the other side of the Arno, to the Golfolina stone, Sheet 8 v., 9 r. Montelupo Sheet 8 v.; 31 v. and San Miniato al Tedesco. Sheet 9 r. Leonardo is also most precise in speaking of the geological events of the area between Arezzo and Florence. Sheet 9 r. But, more than the observations recalled here, which one can certainly not attach a decisive value to, it seems that Leonardo’s presence in Tuscany at the time of the compilation of the Leicester manuscript is confirmed by those margin illustrations which very often provide the propositions of the text with examples taken from observations of the Arno For Leonardo’s studies of the Arno and the designs for its canalisation, cf. Baratta, Leonardo da Vinci’s studies for the navigation of the Arno, in the Bulletin of the Italian Geographic Society. Fasc. X-XI, Rome, 1905. and its affluents. These are the sketches, drawn with precise references which may be found on sheets 13 r. (“Ponte Rubaconte. – Below the Bisticci and Cani (ge) giani.10 There is some doubt as regards the interpretation of this name, interrupted by an erasure and followed by the syllable “ga”, which Leonardo usually wrote in place of “gia” Prof. Gotti wrote: “... it is certain that the Canigiani family owned property around Florence and among it I have found that they owned the Belforte castle at Villamagna, another hill (Villamagna is below the “Incontro’’) near Florence and that of Bisticci. It seems to me probable that this place where they had their property may also have been called “dei canigiani”.” – Above the Pescaia della Giustizia. – a b is a sandbank, opposite where the isle of Cocomeri finishes in the middle of the Arno), 15 r. (Rifredi, Arno. – Mugnone, Arno. – Ombrone), With regard to this sketch and the text which it illustrates (“E se la corrente del fiume minore si congiugne contro alla corrente del maggiore con angolo acuto, esso maggiore terrà sempre ringorgate l’acque del fiume minore, e farà retroso massimo nella sua foce, il qual girerà inver l’avvenimento del fiume maggiore”) [if the current of the lesser river joins that of the major at an acute angle it will keep the waters of the lesser river swollen and will have the maximum backward surge at its mouth, which will flow against the current of the major river], it is interesting to note how the example has been chosen, with Leonardo’s clear-sightedness, precisely from a case that was to be the subject of a ruling by the governor of the grand duchy. The mouth of the Ombrone, which joined the Arno in the opposite direction to the course of the river (as can be seen in Leonardo’s sketch) was turned around in the direction of the Arno about halfway through the XVII century, at the advice of Viviani, who left a record of such in his famous Discourse to the Serene Highness Cosimo III Grand-duke of Tuscany on defending oneself from floods and fluvial erosion applied to the Arno around the City of Florence. Written in December 1687. In Florence, MDCLXXXVIII, in the printing-works of Piero Matini, pg. 14 and 24. 16 v. (Above the Rubaconte bridge, at Torricella. – Below the Ceppo hospital), 18 v. (Concavity produced by Mensola, when Arno is low and Mensola full. Arno, Mensola, Mug[n]one, Pesa, Isola”). Cf. again, in Leonardo’s summary of the Atlantic Codex (Sheet 74 v.-b), mention of which is made below: “Pescaia d’Ognisanti”. These sketches and notes are found in the “7 charts” corresponding to sheets from 18-19 to 12-25, see infra, pg. 30. containing the first and numerically most important group of “casi d’acque e di sua fondi”; (cases of waters and their depths) Sheet 12 r. and the choice and specific detail of these characteristic examples has no equivalent in the manuscript, for Lombardy. Another note which may be linked to the occupations and studies of Leonardo in Florence after 1500, is this very brief one: “To’ la Ramondina”, Sheet 2 r. which must be ascribed, as we shall see, see infra, pg. 25-26. to the search for or use of a scientific work; and recalls a similar and probably earlier note: “Cerchi in Firenze della Ramondina” (Look for the Ramondina in Florence) Arundel Codex, Sheet 192 r. (from Richter, op. cit., II, § 1455, p. 437). Richter did not risk rendering the entire sentence, somewhat obscure, and only copied it into the notes. The sheet containing this note, in the Arundel Codex, may belong to the same period of activity, reflected in the memoranda of the folio preceding it, it too particularly intere-