The third text given under No. 747 refers to works executed by Leonardo in France._ 745. The front _a m_ will give light to the rooms; _a e_ will be 6 braccia--_a b_ 8 braccia --_b e_ 30 braccia, in order that the rooms under the porticoes may be lighted; _c d f_ is the place where the boats come to the houses to be unloaded. In order to render this arrangement practicable, and in order that the inundation of the rivers may not penetrate into the cellars, it is necessary to chose an appropriate situation, such as a spot near a river which can be diverted into canals in which the level of the water will not vary either by inundations or drought. The construction is shown below; and make choice of a fine river, which the rains do not render muddy, such as the Ticino, the Adda and many others. [Footnote 12: _Tesino, Adda e molti altri, i.e._ rivers coming from the mountains and flowing through lakes.] The construction to oblige the waters to keep constantly at the same level will be a sort of dock, as shown below, situated at the entrance of the town; or better still, some way within, in order that the enemy may not destroy it [14]. [Footnote: L. 1-4 are on the left hand side and within the sketch given on Pl. LXXIX, No. I. Then follows after line 14, the drawing of a sluicegate--_conca_--of which the use is explained in the text below it. On the page 38a, which comes next in the original MS. is the sketch of an oval plan of a town over which is written "_modo di canali per la citta_" and through the longer axis of it "_canale magior_" is written with "_Tesino_" on the prolongation of the canal. J. P. R.] 746. Let the width of the streets be equal to the average height of the houses. 747. The main underground channel does not receive turbid water, but that water runs in the ditches outside the town with four mills at the entrance and four at the outlet; and this may be done by damming the water above Romorantin. [11]There should be fountains made in each piazza[13]. [Footnote: In the original this text comes immediately after the passage given as No. 744. The remainder of the writing on the same page refers to the construction of canals and is given later, in the "Topographical Notes". Lines 1-11 are written to the right of the plan lines 11-13 underneath it. J. P. R.] [Footnote 10: _Romolontino_ is Romorantin, South of Orleans in France.] _III. Castles and Villas. A. Castles. Pl. LXXX, No. 1 (P. V. fol. 39b; No. d'ordre 2282). The fortified place here represented is said by Vallardi to be the_ "castello" _at Milan, but without any satisfactory reason. The high tower behind the_ "rivellino" _ravelin--seems to be intended as a watch-tower. Pl. LXXX, No. 2 (MS. B, 23b). A similarly constructed tower probably intended for the same use. Pl. LXXX, No. 3 (MS. B). Sketches for corner towers with steps for a citadel.