limits of space and time which we have set ourselves. A subject which on its own would be the object of an interesting series of considerations is offered by the topics which occurred to Leonardo at various times and which he began to discuss at the beginning of the treatise. On sheets 108 v.-b and 361 v.-a of the Atlantic Codex ( dating to the period under Sforza) there is the rough draft of an introduction, with the same intonation and with a similarly pompous style to the prospective introduction of the (Atlantic Codex, sheet 203 r.-a) removed from the treatise by Giovanni Peckham; with the picture given there by Leonardo of the potential damage caused by rivers, compare the more sober principle of sheet 22 r. of the Leicester manuscript. We shall then note the “cominciamento del trattato de l’acqua”[commencement of the treatise on water] found on sheet 55 v. (54 v. in Ravaisson-Mollien, Les mss., etc., vol. I, where it is thus numbered on account of an accidental printing error, corrected, moreover, in the preface) of the A manuscript and the beginning of that analogy between the world and man which Leonardo continues to express so strongly in the Leicester Codex. In this manuscript however, such concept appears to have lost its hierarchical position in the order of the treatise; Leonardo had already focused his attention on the specific element of water, in other words, the drop of water, on its strength of cohesion and traction, and other “minute operazion delle acque” [detailed mechanisms of water] (as Leonardo’s calls them himself in the list recalled on various occasions of the Atlantic Codex), and, under the influence of such considerations, and, perhaps, also of the preliminary propositions of Archimedes De insidentibus in humido (known to Leonardo, as shown by some fragments written in another hand on sheets 153 v.-e and 153 r.-b, c, of the Atlantic Codex, with the indication Archimenidis De insidentibus in humido. Liber secundus in humido), wrote on sheet 25 r. of the Leicester manuscript: “Questi son casi, che ànno a stare nel principio” [These are cases that must be set at the beginning] (cf. also the F manuscript, sheet 66 v.). However some doubt may remain about whether Leonardo intended to place them not at the beginning of the entire treatise but before a part of it. Diversely, the definition of the open sea and a series of other definitions (cf. the Leicester manuscript, 12 v.) and water vocabulary, on sheet 72v. and r., 71 v. of the previous I manuscript, are explicitly noted as the “principio del libro dell’acque” [beginning of the book on water]. Finally cf. the “l’“ordine del primo libro delle acque” [the order of the first book on water], drafted on sheet 12 r. of the late E manuscript, with the repeated definition, in the Leicester manuscript, of what depth and shallowness are, and specifically with an observation by Leonardo on sheet 26 v. of this same manuscript. It is also worth abstaining, for the reason now advanced, to which limits of competence not to be surpassed without consideration should be added, from starting a detailed examination of the contents and worth of the Treatise on water which Leonardo drafted in this manuscript, or of his relations with the origins and progress of science reflected in it. It is not possible, on the contrary, to omit some considerations which prove essential to the understanding of the text on two fronts, one widely used, the other mentioned in the Leicester manuscript. Leonardo’s admiration for Ptolemy’s Cosmography is well known. See note 1 on pg.12; cf. also Solmi, Le fonti, etc., cit., pg. 271-273. This was Leonardo’s most important geographic source; and in fact with the help of Ptolemy’s maps, mountains, seas, river courses and the distribution of the land and seas were studied in the Leicester manuscript. When, with kind help, we set to looking for items of information which would explain Leonardo’s mention, on sheet 34 r., of the river Trigon, Richter (The literary works, etc., cit., II, § 1095, pg. 264) acted on his own authority to replace the words “trigon” and “minore africha » with “Tigri” and “Asia Minore» which he renders however in the original note; thus not leaving a useful outline for the interpretation of this passage by those examining the same note after him. and the Munace swamp, nominated by him with the other two swamps Pallas and Triton, Cf. the article Triton in Smith’s Dictionary of Greek and Roman geography (London, 1856-57, II, pg. 1233). we were led to consult the edition of Ptolemy’s Cosmography Lastly: clavdii ptolomei viri a / lexandrini cosmographie / octavvs et vltimvs liber explicit opus donnini nicolai germa / ni secvndum ptolomevm / finit anno m cccc lxxxii . avgv / sti vero kalendas. xvii. / impr[e]ssvm vlme per ingeni / osvm virvm leonardvm / hol prefati oppidi civis. printed in Ulm in 1482, and we found clarification not just of this specific point, but traces of most of the cosmographic considerations (except for those regarding the regions of Italy known to him Cf. however the name Adriano (sheet 31 v.) with the Atrianus in table V of Ptolemy’s Europae in both editions, which we compare since under this name the course of the Adige river which Leonardo had already mentioned, is shown therein. contained in the Leicester manuscript, and the reason for the characteristics offered by the geographic nomenclature. We are referring to the 1482 edition, not the Roman edition of 1490, Hoc opus Ptholomei memorabile quidem et insigne exactissima diligentia castigatum iucondo quodam caractere impressum fuit et completum Rome anno a Nativitate Domini. M . CCCCLXXXX. die . IV. Novembris . arte ac impensis Petri de Turre. Solmi (op. cit, pg. 272) grants this edition a preference which does not appear justified. Cf. Brunet (Manuel, vol. cit., col. 951 and 954), for the derivation of the tables contained in the 1490 edition from that of the edition, also printed in Rome, for Arnoldus Buckinck, in 1478; and for their reappearance in the edition, once again printed in Rome, for Evangelista Tosinus, in [1507?] 1508. because certain coincidences may be attributed to the first or other editions Another edition; Impressum Ulme opera et expensis Justi de Albano de Venetiis per provisorem suum Johannem Reger Anno Domini M. CCCC. LXXXVI XII Kalendas Augusti, in fol.; contains (cf. also Brunet, Manuel, IV, IIa partie, Paris, 1863, col. 953-954) the same tables. Of these Brunet indicates a specimen in parchment existing at the Magliabechiana of Florence. or maps (and the hypothesis that Leonardo had designed one or more, Leonardo speaks of a world map of his own, which might have been reproduced on the tables used for the Ulm edition, on sheet 120 r.-d of the Atlantic Codex (see above pg. 16, note 12 and pg. 17, note 2 for the date of such annotation and its relation to Leonardo’s other notes). drawing on the Cosmography, adding then, perhaps some new information, and using them for the Leicester manuscript, would be plausible), which are closely related to his illustrations.