BOOK 43. OF THE MOVEMENT OF AIR ENCLOSED IN WATER.

I have seen motions of the air so furious that they have carried,
mixed up in their course, the largest trees of the forest and whole
roofs of great palaces, and I have seen the same fury bore a hole
with a whirling movement digging out a gravel pit, and carrying
gravel, sand and water more than half a mile through the air.

[Footnote: The first sixteen lines of this passage which treat of
the subject as indicated on the title line have no place in this
connexion and have been omitted.]

[Footnote 2: _Ho veduto movimenti_ &c. Nothing of the kind happened
in Italy during Leonardo's lifetime, and it is therefore extremely
probable that this refers to the natural phenomena which are so
fully described in the foregoing passage. (Compare too, No. 1021.)
There can be no doubt that the descriptions of the Deluge in the
Libro di Pittura (Vol. I, No. 607-611), and that of the fall of a
mountain No. 610, l. 17-30 were written from the vivid impressions
derived from personal experience. Compare also Pl. XXXIV-XL.]