Canal of Florence.

Florence – Prato – Pistoia – Serravalle – Lake – Lucca – Pisa.

Let such sluice-gates be made at the Chiana marshes of Arezzo that, when water fails in the Arno in summer, the canal does not run dry. And let this canal be made 20 braccia wide at the bottom and 30 at the mouth, and always 2 braccia of water, or 4, because two of those braccia would serve the mills and the meadows. This will improve the country; and Prato, Pistoia and Pisa together with Florence will be better by two hundred thousand ducats a year, and they will lend their hands and expense to this aid, and the Lucchesi likewise. Because the lake of Sesto will be navigable, one must take the way of Prato and Pistoia and cut through Serravalle and come out into the lake, for there is no need of locks or supports, which are not eternal but always require labour to work and maintain them.

And know that if, digging the canal where it is 4 braccia deep, one gives 4 dinari per square braccio, at double the depth one gives 6 dinari. If you make 4 braccia, there are only 2 banks, that is, one from the bottom of the ditch to the surface of its lips, and the other from those lips to the top of the mound of earth raised on the bank's edge. And if it were of double depth, that bank grows by only one bank, that is 4 braccia, which adds half the first cost; that is, where before in two banks one gave 4 dinari, in 3 it comes to 6 dinari, at 2 dinari per bank, the ditch being 16 braccia at the bottom. Again, if the ditch were 16 braccia wide and 4 deep, coming to 4 soldi per job, 4 Milanese dinari the square braccio, the ditch that at the bottom will be 32 braccia will come to 8 dinari the square braccio.