The Notebooks of Leonardo Da Vinci (76 page)

On the natives of hot countries.

1112.

Men born in hot countries love the night because it refreshes them
and have a horror of light because it burns them; and therefore they
are of the colour of night, that is black. And in cold countries it
is just the contrary.

[Footnote: The sketch here inserted is in MS. H3 55b.]

Naval Warfare.—Mechanical Appliances.—Music.

Such theoretical questions, as have been laid before the reader in
Sections XVI and XVII, though they were the chief subjects of
Leonardo's studies of the sea, did not exclusively claim his
attention. A few passages have been collected at the beginning of
this section, which prove that he had turned his mind to the
practical problems of navigation, and more especially of naval
warfare. What we know for certain of his life gives us no data, it
is true, as to when or where these matters came under his
consideration; but the fact remains certain both from these notes in
his manuscripts, and from the well known letter to Ludovico il Moro
(No.
1340_), in which he expressly states that he is as capable as
any man, in this very department._

The numerous notes as to the laws and rationale of the flight of
birds, are scattered through several note-books. An account of these
is given in the Bibliography of the manuscripts at the end of this
work. It seems probable that the idea which led him to these
investigations was his desire to construct a flying or aerial
machine for man. At the same time it must be admitted that the notes
on the two subjects are quite unconnected in the manuscripts, and
that those on the flight of birds are by far the most numerous and
extensive. The two most important passages that treat of the
construction of a flying machine are those already published as Tav.
XVI, No.
1
and Tav. XVIII in the
"Saggio delle opere di Leonardo
da Vinci"
(Milan
1872_). The passages—Nos._ 1120-1125—
here
printed for the first time and hitherto unknown—refer to the same
subject and, with the exception of one already published in the
Saggio— No.
1126—
they are, so far as I know, the only notes,
among the numerous observations on the flight of birds, in which the
phenomena are incidentally and expressly connected with the idea of
a flying machine.

The notes on machines of war, the construction of fortifications,
and similar matters which fall within the department of the
Engineer, have not been included in this work, for the reasons given
on page
26
of this Vol. An exception has been made in favour of
the passages Nos.
1127
and
1128,
because they have a more
general interest, as bearing on the important question: whence the
Master derived his knowledge of these matters. Though it would be
rash to assert that Leonardo was the first to introduce the science
of mining into Italy, it may be confidently said that he is one of
the earliest writers who can be proved to have known and understood
it; while, on the other hand, it is almost beyond doubt that in the
East at that time, the whole science of besieging towns and mining
in particular, was far more advanced than in Europe. This gives a
peculiar value to the expressions used in No.
1127.

I have been unable to find in the manuscripts any passage whatever
which throws any light on Leonardo's great reputation as a musician.
Nothing therein illustrates VASARPS well-known statement:
Avvenne
che morto Giovan Galeazze duca di Milano, e creato Lodovico Sforza
nel grado medesimo anno 1494, fu condotto a Milano con gran
riputazione Lionardo al duca, il quale molto si dilettava del suono
della lira, perche sonasse; e Lionardo porto quello strumento
ch'egli aveva di sua mano fabbricato d'argento gran parte, in forma
d'un teschio di cavallo, cosa bizzarra e nuova, acciocche l'armonia
fosse con maggior tuba e piu sonora di voce; laonde supero tutti i
musici che quivi erano concorsi a sonare.

The only notes on musical matters are those given as Nos.
1129
and
1130,
which explain certain arrangements in instruments.

The ship's logs of Vitruvius, of Alberti and of Leonardo

1113.

The ancients used various devices to ascertain the distance gone by
a ship each hour, among which Vitruvius [Footnote 6: See VITRUVIUS,
De Architectura lib. X.
C. 14 (p. 264 in the edition of Rose and
Muller- Strubing). The German edition published at Bale in 1543 has,
on fol. 596, an illustration of the contrivance, as described by
Vitruvius.] gives one in his work on Architecture which is just as
fallacious as all the others; and this is a mill wheel which touches
the waves of the sea at one end and in each complete revolution
describes a straight line which represents the circumference of the
wheel extended to a straightness. But this invention is of no worth
excepting on the smooth and motionless surface of lakes. But if the
water moves together with the ship at an equal rate, then the wheel
remains motionless; and if the motion of the water is more or less
rapid than that of the ship, then neither has the wheel the same
motion as the ship so that this invention is of but little use.
There is another method tried by experiment with a known distance
between one island and another; and this is done by a board or under
the pressure of wind which strikes on it with more or less
swiftness. This is in Battista Alberti [Footnote 25: LEON BATTISTA
ALBERTI,
De Architectura lib. V.
, c. 12 treats '
de le navi e
parti loro
', but there is no reference to the machine, mentioned by
Leonardo. Alberti says here:
Noi abbiamo trattato lungamente in
altro luogo de' modi de le navi, ma in questo luogo ne abbiamo detto
quel tanto che si bisogna
. To this the following note is added in
the most recent Italian edition:
Questo libro e tuttora inedito e
porta il titolo, secondo Gesnero di
'
Liber navis
'.].

Battista Alberti's method which is made by experiment on a known
distance between one island and another. But such an invention does
not succeed excepting on a ship like the one on which the experiment
was made, and it must be of the same burden and have the same sails,
and the sails in the same places, and the size of the waves must be
the same. But my method will serve for any ship, whether with oars
or sails; and whether it be small or large, broad or long, or high
or low, it always serves [Footnote 52: Leonardo does not reveal the
method invented by him.].

Methods of staying and moving in water

1114.

How an army ought to cross rivers by swimming with air-bags … How
fishes swim [Footnote 2: Compare No. 821.]; of the way in which they
jump out of the water, as may be seen with dolphins; and it seems a
wonderful thing to make a leap from a thing which does not resist
but slips away. Of the swimming of animals of a long form, such as
eels and the like. Of the mode of swimming against currents and in
the rapid falls of rivers. Of the mode of swimming of fishes of a
round form. How it is that animals which have not long hind quartres
cannot swim. How it is that all other animals which have feet with
toes, know by nature how to swim, excepting man. In what way man
ought to learn to swim. Of the way in which man may rest on the
water. How man may protect himself against whirlpools or eddies in
the water, which drag him down. How a man dragged to the bottom must
seek the reflux which will throw him up from the depths. How he
ought to move his arms. How to swim on his back. How he can and how
he cannot stay under water unless he can hold his breath [13]. How
by means of a certain machine many people may stay some time under
water. How and why I do not describe my method of remaining under
water, or how long I can stay without eating; and I do not publish
nor divulge these by reason of the evil nature of men who would use
them as means of destruction at the bottom of the sea, by sending
ships to the bottom, and sinking them together with the men in them.
And although I will impart others, there is no danger in them;
because the mouth of the tube, by which you breathe, is above the
water supported on bags or corks [19].

[Footnote: L. 13-19 will also be found in Vol. I No. 1.]

On naval warfare (1115. 1116).

1115.

Supposing in a battle between ships and galleys that the ships are
victorious by reason of the high of heir tops, you must haul the
yard up almost to the top of the mast, and at the extremity of the
yard, that is the end which is turned towards the enemy, have a
small cage fastened, wrapped up below and all round in a great
mattress full of cotton so that it may not be injured by the bombs;
then, with the capstan, haul down the opposite end of this yard and
the top on the opposite side will go up so high, that it will be far
above the round-top of the ship, and you will easily drive out the
men that are in it. But it is necessary that the men who are in the
galley should go to the opposite side of it so as to afford a
counterpoise to the weight of the men placed inside the cage on the
yard.

1116.

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.

The use of swimming belts.

1117.

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]

On the gravity of water.

1118.

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).

1119.

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.]

1120.

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.]

1121.

A definition as to why a man who slides on ice does not fall.
[Footnote: An indistinct sketch accompanies the passage, in the
original.]

On Flying machines (1122-1126).

1122.

Man when flying must stand free from the waist upwards so as to be
able to balance himself as he does in a boat so that the centre of
gravity in himself and in the machine may counterbalance each other,
and be shifted as necessity demands for the changes of its centre of
resistance.

1123.

Remember that your flying machine must imitate no other than the
bat, because the web is what by its union gives the armour, or
strength to the wings.

If you imitate the wings of feathered birds, you will find a much
stronger structure, because they are pervious; that is, their
feathers are separate and the air passes through them. But the bat
is aided by the web that connects the whole and is not pervious.

1124.

Destruction to such a machine may occur in two ways; of which the
first is the breaking of the machine. The second would be when the
machine should turn on its edge or nearly on its edge, because it
ought always to descend in a highly oblique direction, and almost
exactly balanced on its centre. As regards the first—the breaking
of the machine—, that may be prevented by making it as strong as
possible; and in whichever direction it may tend to turn over, one
centre must be very far from the other; that is, in a machine 30
braccia long the centres must be 4 braccia one from the other.

[Footnote: Compare No. 1428.]

1125.

Bags by which a man falling from a height of 6 braccia may avoid
hurting himself, by a fall whether into water or on the ground; and
these bags, strung together like a rosary, are to be fixed on one's
back.

1126.

An object offers as much resistance to the air as the air does to
the object. You may see that the beating of its wings against the
air supports a heavy eagle in the highest and rarest atmosphere,
close to the sphere of elemental fire. Again you may see the air in
motion over the sea, fill the swelling sails and drive heavily laden
ships. From these instances, and the reasons given, a man with wings
large enough and duly connected might learn to overcome the
resistance of the air, and by conquering it, succeed in subjugating
it and rising above it. [Footnote: A parachute is here sketched,
with an explanatory remark. It is reproduced on Tav. XVI in the
Saggio, and in:
Leonardo da Vinci als Ingenieur etc., Ein Beitrag
zur Geschichte der Technik und der induktiven Wissenschaften, von
Dr. Hermann Grothe, Berlin
1874, p. 50.]