bridges, tunnels, canals, fortifications, the making of cannon, use
of combustibles and explosives--known to him alone--he gets down to
things of peace and says: "I believe I am equaled by no one in
architecture in constructing public and private buildings, and in
conducting water from one place to another. I can execute sculpture,
whether in marble, bronze or terra cotta, and in drawing and
painting I believe I can do as much as any other man, be he who he
may. Further, I could engage to execute the bronze statue in memory
of your honored father. And again, if any of the above-mentioned
things should appear impossible or overstated, I am ready to make
such performance in any place or at any time to prove to you my
power. In humility I thus commend myself to your illustrious house,
and am your servant, Leonardo da Vinci."

And the strange part of all this is that Leonardo could do all he
claimed--or he might, if there were a hundred hours in a day and man
did not grow old.

The things he predicted and planned have mostly been done. He knew
the earth was round, and understood the orbits of the planets--
Columbus knew no more. His scheme of building a canal from Pisa to
Florence and diverting the waters of the Arno, was carried out
exactly as he had planned, two hundred years after his death. He
knew the expansive quality of steam, the right systems of dredging,
the action of the tides, the proper use of levers, screws and
cranes, and how immense weights could be raised and lowered. He
placed a new foundation under a church that was sinking in the sand
and elevated the whole stone structure several feet. But when Vasari
seriously says he had a plan for moving mountains (aside from
faith), I think we had better step aside and talk of other things.