If you want to build an armada for the sea employ these ships to ram in the enemy's ships. That is, make ships 100 feet long and 8 feet wide, but arranged so that the left hand rowers may have their oars to the right side of the ship, and the right hand ones to the left side, as is shown at M, so that the leverage of the oars may be longer. And the said ship may be one foot and a half thick, that is made with cross beams within and without, with planks in contrary directions. And this ship must have attached to it, a foot below the water, an iron-shod spike of about the weight and size of an anvil; and this, by force of oars may, after it has given the first blow, be drawn back, and driven forward again with fury give a second blow, and then a third, and so many as to destroy the other ship.
A METHOD OF ESCAPING IN A TEMPEST AND SHIPWRECK AT SEA.
Have a coat made of leather, which must be double across the breast, that is having a hem on each side of about a finger breadth. Thus it will be double from the waist to the knee; and the leather must be quite air-tight. When you want to leap into the sea, blow out the skirt of your coat through the double hems of the breast; and jump into the sea, and allow yourself to be carried by the waves; when you see no shore near, give your attention to the sea you are in, and always keep in your mouth the air-tube which leads down into the coat; and if now and again you require to take a breath of fresh air, and the foam prevents you, you may draw a breath of the air within the coat.
[Footnote: AMORETTI, _Memorie Storiche_, Tav. II. B. Fig. 5, gives the same figure, somewhat altered. 6. _La canna dell' aria_. Compare Vol. I. No. I. Note]
If the weight of the sea bears on its bottom, a man, lying on that bottom and having l000 braccia of water on his back, would have enough to crush him.
Diving apparatus and Skating (1119-1121).
Of walking under water. Method of walking on water.
[Footnote: The two sketches belonging to this passage are given by AMORETTI, _Memorie Storiche_. Tav. II, Fig. 3 and 4.]
Just as on a frozen river a man may run without moving his feet, so a car might be made that would slide by itself.
[Footnote: The drawings of carts by the side of this text have no direct connection with the problem as stated in words.--Compare No. 1448, l. 17.]