1011.

No canal which is fed by a river can be permanent if the river whence it originates is not wholly closed up, like the canal of Martesana which is fed by the Ticino.

1012.

>From the beginning of the canal to the mill.

>From the beginning of the canal of Brivio to the mill of Travaglia is 2794 trabochi, that is 11176 braccia, which is more than 3 miles and two thirds; and here the canal is 57 braccia higher than the surface of the water of the Adda, giving a fall of two inches in every hundred trabochi; and at that spot we propose to take the opening of our canal.

[Footnote:  The following are written on the sketches:  At the place marked N:  navilio da dacquiue (canal of running water); at M:  molin del Travaglia (Mill of Travaglia); at R:  rochetta ssanta maria (small rock of Santa Maria); at A:  Adda; at L:  Lagho di Lecho ringorgato alli 3 corni in Adda,—­Concha perpetua (lake of Lecco overflowing at Tre Corni, in Adda,—­ a permanent sluice).  Near the second sketch, referring to the sluice near Q:  qui la chatena ttalie d’u peso (here the chain is in one piece).  At M in the lower sketch:  mol del travaglia, nel cavare la concha il tereno ara chotrapero co cassa d’acqua. (Mill of Travaglia, in digging out the sluice the soil will have as a counterpoise a vessel of water).]

1013.

If it be not reported there that this is to be a public canal, it will be necessary to pay for the land; [Footnote 3:  il re.  Louis XII or Francis I of France.  It is hardly possible to doubt that the canals here spoken of were intended to be in the Milanese.  Compare with this passage the rough copy of a letter by Leonardo, to the "Presidente dell’ Ufficio regolatore dell’ acqua" on No. 1350.  See also the note to No. 745, 1. 12.] and the king will pay it by remitting the taxes for a year.

Estimates and preparatory studies for canals (1014. 1015).

1014.

CANAL.

The canal which may be 16 braccia wide at the bottom and 20 at the top, we may say is on the average 18 braccia wide, and if it is 4 braccia deep, at 4 dinari the square braccia; it will only cost 900 ducats, to excavate by the mile, if the square braccio is calculated in ordinary braccia; but if the braccia are those used in measuring land, of which every 4 are equal to 4 1/2 and if by the mile we understand three thousand ordinary braccia; turned into land braccia, these 3000 braccia will lack 1/4; there remain 2250 braccia, which at 4 dinari the braccio will amount to 675 ducats a mile.  At 3 dinari the square braccio, the mile will amount to 506 1/4 ducats so that the excavation of 30 miles of the canal will amount to 15187 1/2 ducats.

1015.

To make the great canal, first make the smaller one and conduct into it the waters which by a wheel will help to fill the great one.