Having freed the field of the possible deductions regarding the years prior to 1503, one must then compare the Leicester Codex to the other manuscripts, and to the history of Leonardo’s ideas to try and whittle down the period in which the Codex may have been written: a period which Richter The literary works, etc., cit., I, pg. 6. gives as ranging from 1500 to 1516 (with a question mark over 1510 and which should here and now be reduced within narrower limits. In fact, starting from the end of 1510, when Leonardo was busy reaping the fruits of his anatomical studies with Marco Antonio Della Torre, a definite change to the opinion expressed on various occasions in the Leicester manuscript regarding the circulation of water in the world, Dell’Anatomia, sheet A, cit., sheet 4 r., pg. 77: “Contrario è l’origine del mare all’origine del sangue, perché il mare riceve in sé tutti li fiumi, li quali son sol causati dalli vapori acquei levati infra l’aria; ma il mare del sangue è causa di tutte le vene”[the origin of the sea is the contrary of the origin of blood, because the sea receives into itself all the rivers, which are but caused by the water vapour rising into the air; but the sea of blood is the source of all the veins] an opinion diametrically opposed to that expressed in the Leicester manuscript on sheet 21 v., 28 r., 33 v., (cf. also sheet 6 r, 6 v., 11 v., 17 r., 17 v., 31 r.,), and sustained in other manuscripts (cf. mainly ms. A, 55 v., 56 r. and v., and the Atlantic Codex 74 r.-a, 171 r.-a, 309 v.-a, 367 v.-b, 396 r.-a (crossed out passage). The only point (in the Leicester manuscript), where the theory which Leonardo later recognised as erroneous is expressed in dubitative form, is on sheet 35 r., (presumably one of the last time-wise): “Ma, se tali vene avessino l’origine dalli fondi de’ mari”, [But, if such veins had their origin at the bottom of the sea of blood] etc. In the F manuscript, (sheet 1 r.) this concept reappears briefly to give rise to an interesting antithetical observation. Regarding Leonardo’s change of opinion, see also Baratta, Leonardo da Vinci e i problemi della terra, cit., pg. 108-110. compared by him with rigid parallelism to the circulation of blood in animals, shows us that Leonardo had changed his way of thinking in a certain and definitive manner, as one may infer not just from the blunt expression of the passage quoted, but also from later notes belonging to the manuscript G. G manuscript, 38 r., 48 v., 70 r. cf. also Atlantic Codex 160 v.-a (see Baratta, loc. cit.). When Leonardo contradicted – in the Anatomical sheets – what he had so carefully sustained in the Leicester manuscript, he had already been in Milan for at least two years, Cf. Dell’Anatomia, sheets A, cit., sheet 17 r., pg. 179: “e questa vernata del mille (5010) 510 credo spedire tutta tal notomia”. [and this winter of the year one thousand 510 I shall send off all of this anatomy] that is presumably since the spring of 1508. We know (see note 4 on pg. 11), that Leonardo was still in Florence on 22 March 1508; and that he planned (cf. Atlantic Codex, sheet 317 r.-b, 372 v.-a) to be back in Milan by Easter (23 April) of that year; but his return may have been postponed. For the reasons already cited, which induce one to believe that the Codex was compiled mainly in Florence, further investigation would seem to rule out any time later than 1508. It is to this year that the first sheets of the Arundel Codex must refer, See note 4 on pg. 11. To the extent that it may be believed that sheets 1 r. to 30 v. of the Arundel Codex may be attributed to the original structure of the manuscript begun in March 1508 at the house of Piero di Braccio Martelli. Cf. also Richter, The literary works, etc., cit., II, pg. 49 and, to the subsequent months, the manuscript F, Cf. F manuscript, sheet 1 r.: “Cominciato a Milano, addì 12 di settembre 1508”. [Begun in Milan on the day of 12 September 1508] which offer, the former As well as the analogies indicated in note 4 on pg. 11, other points of contact would be offered by resuming, which the Arundel Codex does, (sheet 29 r.), the study of the way in which the mountains were hewn and the valleys and plains between them formed as a consequence of the water courses, from the point where Leonardo leaves it in his note at the top of sheet 1 v. of the Leicester manuscript; drawing once again from Tuscan examples “Sasso saldo di Mugnone cavato for de [forte [?] dall’acqua in forma di vasi; pare opra manuale, tanto è a punto – ”[the vase-shaped solid rock of the Mugnone pulled [strongly?] out of the water, seems to have been fashioned by hand it is so well formed] - (Arundel Codex, sheet 29 v., to be compared with the subsequent sheet, also as regards other water themes, such as for example, this one: “Libro 7°, dell’acqua, che con varie qualità d’angoli percuote e cava sotto l’argine de’ fiumi – ”, [7th Book, on water, which at various angles strikes and excavates from under the river bank] - cf. sheet 31 v.); repeating (ibid: “Molti sono li monti, de’ quali li sassi, di che essi sono composti, non pa(r)ssan le radici di tali monti, ma, seguitando il medesimo ordine delle falde, son convertiti in tufo, e sotto al tufo è lita: e questo si vede ne’ lati di tutti li fiumi, che escan de’ gran tagli de’ monti nelle gran pianure, li quali à segati li monti insino alle loro radici – ”) [there are many mountains formed of rocks which do not extend beyond their slopes but which following the same order as the strata, have been converted into tufa, and under the tufa, gravel; and this can be seen on the banks of all the rivers that come out into the plains from great cracks in the mountains, which they have cut right down to their feet] a concept already expressed on sheet 36r.; finally from the fragments relative to the spots on the moon (Arundel Codex, 19 r., Richter, op. cit., II, § 906), to the prospect of the reflection of water and the effects of the moon (Arundel Codex, 25 r. (Richter, op. cit., II, § 875), and 28 r. (Richter, op. cit. II, § 876 and 895), a theme dealt with again in the F manuscript, sheets 39 r., 40 r., 61, 62 v., 63 r. and v., 76 r., 77 v. (to be compared specifically with sheet 30 r. of the Leicester manuscript), 93r. Many of the sheets of the Atlantic Codex address this same subject, sometimes (cf. sheet 243 r. and v.) in almost identical terms to that of the Leicester manuscript. It should however be noted that Leonardo started this series of reflections early on (cf. ms. (Ash.) 2038 of the Paris National Library, sheet 16 v., and manuscript C, sheet 17 v.) and later developed them. and the latter, considerable coincidences with the Leicester manuscript and, specifically, with the last two sheets of this Codex. As well as what has been indicated for manuscript F. in the previous note, it may be observed how the following themes reappear (sometimes with considerable coincidences) in the same manuscript, touched on in the Leicester manuscript on sheets: 28 r. and 30 r. (Log (cf. manuscript. F, 48 v.) interpreted differently by Ravaisson-Mollien, in his transcription, and by Baratta (op. cit., pg. 42), since Leonardo omitted on line 1 the word “navilio”[naval craft]; but the comparison with the Leicester code and the dimensions of the device confirm that we are speaking of a ship’s log and not an odometer); 30 v. (Durata delle impressioni nell’acqua [Duration of impressions in water] (cf. ms. F, 71 r. and 21 v.) Ghiareto sollevato dal vento [Gravel raised by the wind]; (cf. ms. F, 37 v.). L’acqua per sé non si move, s’ella non discende [Water in itself does not move, unless flowing downwards] (cf. ms. F. 82 v.; the same proposition is found in various places in the manuscripts); 31 r. and v., 32 v. (Livello del mare e altezza delle montagne: [The level of the sea and height of mountains] see below, in this note, the considerations offered by a comparison of the two); 6 v. (Legge delle portate [The laws of flow]; cf. ms. F, 68 v.); 32 v. Mutazione della terra intorno al centro dei nostri elementi [The changes in the earth around the centre of our elements]; cf. ms. F, 70 r., 52 v.); 5 r. (Macchie della luna [Moon spots]; cf. ms. F, 84 r. and v., 85 r., and Duhem (P.), Etudes sur Léonard de Vinci. Ceux qu’il a lus et ceux qui l’ont lu. Première série (Paris, Hermann, 1906) pg. 22-23); 33 v. (Montagne di Scizia [The Scizia Mountains]; cf. ms. F, 86 r.); 4 r. and 36 r. (Causa dell’azzurro dell’aria; azzurro del fumo di legne secche [The causes of the blue of the sky; the blue of dry wood smoke]; cf. ms. F, 18 r.); 34 r. (Caldo, anima del mondo [Heat, the essence of the world]; cf. ms. F, 4 v.); 2 v. (Prosciugamento di stagno, che sbocchi nel mare [The drying out of a pond which empties into the sea]; cf. ms. F, 13 r., 15 r., 40 v.); 35 r. and 36 r. (Suoli o gradi dei fanghi, e pietrificazioni[ Soils, or types of mud and petrification]; cf. ms. F, 78 v., 79 r. and v, 80 r. and v.); 35 v. and 36 r. (I tre centri dei corpi; come non coincidano nella sfera della terra né nella sfera dell’acqua; comparazioni tra la terra coperta e la terra scoperta dalla sfera dell’acqua; mutazione della terra [ the three centres of bodies; how they fail to coincide in the sphere of the earth or in the sphere of water; a comparison of the earth covered and uncovered by a body of water; changes in the earth ] , as above; cf. ms. F, 52 v., 55 r., 69 r., 70 r.); 36 r. (Moto dell’acqua su un piano [the motion of water on a flat plane]; cf. ms. F, 82 v.); 36 v. (Onda del vaso circolare [water waves in a round tank]; cf. ms. F, 75 v.). other reasons for comparison can be found for the rest of the Leicester manuscript; I shall limit myself here to noting the question which Leonardo plans to pose (ms. F, verso of the cover sheet) to the master Maffeo to find out the causes of the septenial low and high waters of the river Adige (cf. ms. Leicester, 20 r., pg. 98, pg. 112), and the observation (ms. F, 82 r.) in contrast to a rule of Leon Battista Alberti (cf. ms. Leicester, sheet 13 r. also the references already given for the log). It may seem strange that the theory of those claiming that the level of the sea was higher than that of the mountain peaks - a theory rejected in the Leicester manuscript on sheets 31 r., and v., 32 v., and even earlier in manuscript A, on sheet 56 r. and v., 58 v. (cf. also the Atlantic Codex, 80 v.-b; and see Baratta, op. cit, chap. V, pg. 56-75, and op. and vol. cit. (pg. 177 and subsequent) of Duhem who seems to me in this case not to have sufficient regard for Leonardo’s page order and the sense of his notes) - should have once again resumed the status of an admissible and debatable question on sheet 50 r. of ms. F. But it is worth pointing out here that Leonardo had raised an objection and a contradiction on the same page of the Leicester manuscript (sheet 31 r. cit.), in which he rejected that error, and in others (10 r.; 35 r.) of the Leicester manuscript and of other manuscripts (cf. especially sheets 263 v.-b of the Atlantic Codex), suggesting that the Mediterranean (destined one day, after being gradually sucked into the earth, to become a just river flowing through the Mediterranean basin) had a current which took most of the water flowing into it from the tributary rivers, to the ocean through the strait of Gibraltar; observing, on the contrary, (sheet 31 r.) that the water of the Mediterranean, having abandoned (after the Gaditan strait had formed) the course it once followed for the Red Sea, “sempre ànno poi versato per lo stretto di Spagna”.[ has always flowed towards the Spanish strait]. Now Leonardo, conforming to some of his premises regarding the ullage required to make water move (Leicester manuscript 15 r., 19 r., compare especially with sheet 352 v.-a of the Atlantic Codex, 21 v.; cf. ms. F, 50 r. and v.) and regarding the equilibrium of liquids in communicating vessels (cf. Leicester manuscript, sheet 7 v.) finds himself faced with (ms. F, 68 v.-68 r.) a “bel quesito”[interesting question], strictly connected with the one we are dealing with, given the reference made by Leonardo to the difference in level which he deduces exists between the “il mare della Tana, che confina col Tanai””[the Tana sea bordering on the Tanai”] and the strait of Gibraltar where the Mediterranean is higher (between the two points mentioned) than any mountain in the western world “che monte che abbia l’Occidente.” One must immediately say however that the reaction to such an erroneous theory regarding the level of the sea compared to the height of mountains arrives promptly and readily in the same manuscript F, and in general how the opinions embraced are rejected, in a very unusual note on sheet 72 v. (cf. also sheet 73 r.): “Se l’acqua, che surge pell’alte cime de’ monti, viene dal mare, del quale il suo peso (la) su la sospignie per essere più alto d’essi monti, perché a così licenzia tal particula d’acqua a levarsi in tanta altezza (e ne resta) e penetrare la terra con tanta difficultà e tempo, e non è stato conceduto al resto dell’elemento dell’acqua fare il simile, il quale confina coll’aria, la qual non è per resisterli che ‘l tutto non si elevassi alla medesima altezza della predetta parte? a [o] tu, che tale invenzione trovasti, rito[r]na a rimparare naturale, che tu mancherai di tali simili openioni, del quale tu a’ fatto grande ammunizione, insieme col capitale del frate, che tu possiedi”. [If the water which springs from the highest peaks of the mountains comes from the sea, which by its weight pushes it up there because it is deeper than the mountain itself, then why does this water rise up to such a height and remain there and penetrate the earth, something in itself most difficult and which requires time and yet cannot do the same in the air which opposes less resistance, and reach the same height? You who have discovered this theory, go back and learn from nature and you shall see that you will no longer give such opinions, of which you have made great admonishments, together with the monk’s capital you own.] in which Leonardo appears to attribute that opinion to the author consulted, or to the person who had supplied him with such opinion (cf. Duhem, op. and vol. cit., pg. 181); since the word “frate”[monk], which Solmi (Le fonti, etc., cit., pg. 57) believes as mistakenly interpreted by Ravaisson-Mollien and accepted by Duhem (whom I would rather say had failed to understand the general meaning of the passage) instead of “frutto” [fruit] is too obvious to have been replaced with another.