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VOLUME II - SECTION XVIII. 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.
ON MOVEMENTS;--TO KNOW HOW MUCH A SHIP ADVANCES IN AN HOUR.
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)
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)
1117.
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]
On the gravity of water (1118)
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.
TO ESCAPE THE PERIL OF DESTRUCTION.
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.]
Of mining (1127)
1127.
If you want to know where a mine runs, place a drum over all the
places where you suspect that it is being made, and upon this drum
put a couple of dice, and when you are over the spot where they are
mining, the dice will jump a little on the drum at every blow which
is given underground in the mining.
There are persons who, having the convenience of a river or a lake
in their lands, have made, close to the place where they suspect
that a mine is being made, a great reservoir of water, and have
countermined the enemy, and having found them, have turned the water
upon them and destroyed a great number in the mine.
Of Greek fire (1128)
1128.
GREEK FIRE.
Take charcoal of willow, and saltpetre, and sulphuric acid, and
sulphur, and pitch, with frankincense and camphor, and Ethiopian
wool, and boil them all together. This fire is so ready to burn that
it clings to the timbers even under water. And add to this
composition liquid varnish, and bituminous oil, and turpentine and
strong vinegar, and mix all together and dry it in the sun, or in an
oven when the bread is taken out; and then stick it round hempen or
other tow, moulding it into a round form, and studding it all over
with very sharp nails. You must leave in this ball an opening to
serve as a fusee, and cover it with rosin and sulphur.
Again, this fire, stuck at the top of a long plank which has one
braccio length of the end pointed with iron that it may not be burnt
by the said fire, is good for avoiding and keeping off the ships, so
as not to be overwhelmed by their onset.
Again throw vessels of glass full of pitch on to the enemy's ships
when the men in them are intent on the battle; and then by throwing
similar burning balls upon them you have it in your power to burn
all their ships.
[Footnote: Venturi has given another short text about the Greek fire
in a French translation (Essai Section XIV). He adds that the
original text is to be found in MS. B. 30 (?). Libri speaks of it in
a note as follows (_Histoire des sciences mathematiques en Italie
Vol. II_ p. 129): _La composition du feu gregeois est une des chases
qui ont ete les plus cherchees et qui sont encore les plus
douteuses. On dit qu'il fut invente au septieme siecle de l'ere
chretienne par l'architecte Callinique (Constantini Porphyrogenetae
opera, Lugd. Batav._ 1617,-- _in-_8vo; p. 172, _de admin, imper.
exp._ 48_), et il se trouve souvent mentionne par les Historiens
Byzantins. Tantot on le langait avec des machines, comme on
lancerait une banche, tantot on le soufflait avec de longs tubes,
comme on soufflerait un gaz ou un liquide enflamme (Annae Comnenae
Alexias_, p. 335, _lib. XI.--Aeliani et Leonis, imperatoris tactica,
Lugd.-Bat._ 1613, _in_-4. part. 2 a, p. 322, _Leonis tact. cap._
l9.--_Joinville, histoire du Saint Louis collect. Petitot tom. II,_
p. 235). _Les ecrivains contemporains disent que l'eau ne pouvait
pas eteindre ce feu, mais qu'avec du vinaigre et du sable on y
parvenait. Suivant quelques historiens le feu gregeois etait compose
de soufre et de resine. Marcus Graecus (Liber ignium, Paris,_ 1804,
_in_-40_) donne plusieurs manieres de le faire qui ne sont pas tres
intelligibles, mais parmi lesquelles on trouve la composition de la
poudre a canon. Leonard de Vinci (MSS. de Leonard de Vinci, vol. B.
f. 30,) dit qu'on le faisait avec du charbon de saule, du salpetre,
de l'eau de vie, de la resine, du soufre, de la poix et du camphre.
Mais il est probable que nous ne savons pas qu'elle etait sa
composition, surtout a cause du secret qu'en faisaient les Grecs. En
effet, l'empereur Constantin Porphyrogenete recommende a son fils de
ne jamais en donner aux Barbares, et de leur repondre, s'ils en
demandaient, qu'il avait ete apporti du ciel par un ange et que le
secret en avait ete confie aux Chretiens (Constantini
Porphyrogennetae opera,_ p. 26-27, _de admin. imper., cap. _12_)._]
Of Music (1129-1130)
1129.
A drum with cogs working by wheels with springs [2].
[Footnote: This chapter consists of explanations of the sketches
shown on Pl. CXXI. Lines 1 and 2 of the text are to be seen at the
top at the left hand side of the first sketch of a drum. Lines 3-5
refer to the sketch immediately below this. Line 6 is written as the
side of the seventh sketch, and lines 7 and 8 at the side of the
eighth. Lines 9-16 are at the bottom in the middle. The remainder of
the text is at the side of the drawing at the bottom.]
A square drum of which the parchment may be drawn tight or slackened
by the lever _a b_ [5].
A drum for harmony [6].
[7] A clapper for harmony; that is, three clappers together.
[9] Just as one and the same drum makes a deep or acute sound
according as the parchments are more or less tightened, so these
parchments variously tightened on one and the same drum will make
various sounds [16].
Keys narrow and close together; (bicchi) far apart; these will be
right for the trumpet shown above.
_a_ must enter in the place of the ordinary keys which have the ...
in the openings of a flute.
1130.
Tymbals to be played like the monochord, or the soft flute.
[6] Here there is to be a cylinder of cane after the manner of
clappers with a musical round called a Canon, which is sung in four
parts; each singer singing the whole round. Therefore I here make a
wheel with 4 teeth so that each tooth takes by itself the part of a
singer.
[Footnote: In the original there are some more sketches, to which
the text, from line 6, refers. They are studies for a contrivance
exactly like the cylinder in our musical boxes.]
Of decorations (1131)
1131.
White and sky-blue cloths, woven in checks to make a decoration.
Cloths with the threads drawn at _a b c d e f g h i k_, to go round
the decoration. _
Read next: VOLUME II: SECTION XIX. PHILOSOPHICAL MAXIMS. MORALS. POLEMICS AND SPECULATIONS
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