discende d’una (certa) data altezza, della quale altezza sempre mette una terminata quantità d’acqua”, essa quantità non mancherà mai del suo ordine per nessuno ostaculo, che far si potessi più basso che la prima caduta dell’acqua” . [water which flows down from a (certain) height has a constant flow and maintains such flow independently of the obstacles it finds lower down along its course] If the date of 1499, given for the news recalled , is correct; and if Leonardo’s opinion on the repairs to be made to combat the slippage of Monte S.Salvadore was not obtained indirectly (which appears unlikely), then one must admit that Leonardo, after the unexpected catastrophe of the Sforza in 1499, initially took refuge in Florence , or that he moved from Venice to Florence (where he appears to have been on 24 April 1500) , and that he had given his opinion and his diagram regarding Monte S. Salvadore before 25 March 1500, in other words just a few days before Lorenzo Gusnasco da Pavia, writing to Isabella d’Este, confirmed Leonardo’s presence in Venice. Certainly, there is some difficulty here in making the dates tally, and one is inclined to believe that 1499 (noted twice) may have been used to indicate an opinion actually given at a later date. This theory acquires strength, coinciding with the other deductions on the approximate date of the manuscript, and would explain better the modern flavour of the note mentioned in the Leicester manuscript, on the discovery that Milanesi, in the Chronological Summary of the Life and Works of Giuliano and Antonio da San Gallo indicates 1499 as the date of Giuliano’s opinion while in the Chronological Summary of the Life and Works of Leonardo8, he dates Leonardo’s opinion in 1506: a divergence which it is difficult to attribute to a contradiction by Vasari’s expert commentator, though the justification he might have given escapes one. Another observation regarding the notes of the Leicester manuscript which might suggest useful dates for research are provided by the mention of an earthquake happening «‘n una montagnia in Savoia, dove certi boschi profondorono e lasciorono uno balatro profondissimo; e lontano circa 4 miglia di lì s’aperse il terreno in certa spiaggia di monte, e gittò una subita inondazione grossissima d’acqua, la quale nettò tutta una vallata di terreni lavorativi, vignie e case, e fe(g)ce grandissimo danno ovunche discorse».(in a mountain in Savoy, where certain forests disappeared into the ground and left a deep precipice; and about 4 miles away from that place the ground opened up in a certain heap of stones and threw up a great quantity of water which washed away an entire valley of farmlands, vineyards and houses and caused great damage wherever it passed”. But there is some doubt as to which disaster Leonardo was alluding to with these words: Baratta believes that they might refer to the great “landslide” which occurred at the foot of Monte Gra-