The Notebooks of Leonardo Da Vinci (79 page)

He who walks straight rarely falls.

It is bad if you praise, and worse if you reprove a thing, I mean,
if you do not understand the matter well.

It is ill to praise, and worse to reprimand in matters that you do
not understand.

1201.

Words which do not satisfy the ear of the hearer weary him or vex
him, and the symptoms of this you will often see in such hearers in
their frequent yawns; you therefore, who speak before men whose good
will you desire, when you see such an excess of fatigue, abridge
your speech, or change your discourse; and if you do otherwise, then
instead of the favour you desire, you will get dislike and
hostility.

And if you would see in what a man takes pleasure, without hearing
him speak, change the subject of your discourse in talking to him,
and when you presently see him intent, without yawning or wrinkling
his brow or other actions of various kinds, you may be certain that
the matter of which you are speaking is such as is agreeable to him
&c.

1202.

The lover is moved by the beloved object as the senses are by
sensible objects; and they unite and become one and the same thing.
The work is the first thing born of this union; if the thing loved
is base the lover becomes base.

When the thing taken into union is perfectly adapted to that which
receives it, the result is delight and pleasure and satisfaction.

When that which loves is united to the thing beloved it can rest
there; when the burden is laid down it finds rest there.

Politics (1203. 1204).

1203.

There will be eternal fame also for the inhabitants of that town,
constructed and enlarged by him.

All communities obey and are led by their magnates, and these
magnates ally themselves with the lords and subjugate them in two
ways: either by consanguinity, or by fortune; by consanguinity, when
their children are, as it were, hostages, and a security and pledge
of their suspected fidelity; by property, when you make each of
these build a house or two inside your city which may yield some
revenue and he shall have…; 10 towns, five thousand houses with
thirty thousand inhabitants, and you will disperse this great
congregation of people which stand like goats one behind the other,
filling every place with fetid smells and sowing seeds of pestilence
and death;

And the city will gain beauty worthy of its name and to you it will
be useful by its revenues, and the eternal fame of its
aggrandizement.

[Footnote: These notes were possibly written in preparation for a
letter. The meaning is obscure.]

1204.

To preserve Nature's chiefest boon, that is freedom, I can find
means of offence and defence, when it is assailed by ambitious
tyrants, and first I will speak of the situation of the walls, and
also I shall show how communities can maintain their good and just
Lords.

[Footnote: Compare No. 1266.]

Against Speculators (1205. 1206).

1205.

Oh! speculators on things, boast not of knowing the things that
nature ordinarily brings about; but rejoice if you know the end of
those things which you yourself devise.

1206.

Oh! speculators on perpetual motion how many vain projects of the
like character you have created! Go and be the companions of the
searchers for gold. [Footnote: Another short passage in MS. I,
referring also to speculators, is given by LIBRI (
Hist, des
Sciences math.
III, 228):
Sicche voi speculatori non vi fidate
delli autori che anno sol col immaginatione voluto farsi interpreti
tra la natura e l'omo, ma sol di quelli che non coi cienni della
natura, ma cogli effetti delle sue esperienze anno esercitati i loro
ingegni.
]

Against alchemists (1207. 1208).

1207.

The false interpreters of nature declare that quicksilver is the
common seed of every metal, not remembering that nature varies the
seed according to the variety of the things she desires to produce
in the world.

1208.

And many have made a trade of delusions and false miracles,
deceiving the stupid multitude.

Against friars.

1209.

Pharisees—that is to say, friars.

[Footnote: Compare No. 837, 11. 54-57, No. 1296 (p. 363 and 364),
and No. 1305 (p. 370).]

Against writers of epitomes.

1210.

Abbreviators do harm to knowledge and to love, seeing that the love
of any thing is the offspring of this knowledge, the love being the
more fervent in proportion as the knowledge is more certain. And
this certainty is born of a complete knowledge of all the parts,
which, when combined, compose the totality of the thing which ought
to be loved. Of what use then is he who abridges the details of
those matters of which he professes to give thorough information,
while he leaves behind the chief part of the things of which the
whole is composed? It is true that impatience, the mother of
stupidity, praises brevity, as if such persons had not life long
enough to serve them to acquire a complete knowledge of one single
subject, such as the human body; and then they want to comprehend
the mind of God in which the universe is included, weighing it
minutely and mincing it into infinite parts, as if they had to
dissect it!

Oh! human stupidity, do you not perceive that, though you have been
with yourself all your life, you are not yet aware of the thing you
possess most of, that is of your folly? and then, with the crowd of
sophists, you deceive yourselves and others, despising the
mathematical sciences, in which truth dwells and the knowledge of
the things included in them. And then you occupy yourself with
miracles, and write that you possess information of those things of
which the human mind is incapable and which cannot be proved by any
instance from nature. And you fancy you have wrought miracles when
you spoil a work of some speculative mind, and do not perceive that
you are falling into the same error as that of a man who strips a
tree of the ornament of its branches covered with leaves mingled
with the scented blossoms or fruit……. [Footnote 48:
Givstino
,
Marcus Junianus Justinus, a Roman historian of the second century,
who compiled an epitome from the general history written by Trogus
Pompeius, who lived in the time of Augustus. The work of the latter
writer no longer exist.] as Justinus did, in abridging the histories
written by Trogus Pompeius, who had written in an ornate style all
the worthy deeds of his forefathers, full of the most admirable and
ornamental passages; and so composed a bald work worthy only of
those impatient spirits, who fancy they are losing as much time as
that which they employ usefully in studying the works of nature and
the deeds of men. But these may remain in company of beasts; among
their associates should be dogs and other animals full of rapine and
they may hunt with them after…., and then follow helpless beasts,
which in time of great snows come near to your houses asking alms as
from their master….

On spirits (1211—1213).

1211.

O mathematicians shed light on this error.

The spirit has no voice, because where there is a voice there is a
body, and where there is a body space is occupied, and this prevents
the eye from seeing what is placed behind that space; hence the
surrounding air is filled by the body, that is by its image.

1212.

There can be no voice where there is no motion or percussion of the
air; there can be no percussion of the air where there is no
instrument, there can be no instrument without a body; and this
being so, a spirit can have neither voice, nor form, nor strength.
And if it were to assume a body it could not penetrate nor enter
where the passages are closed. And if any one should say that by
air, compressed and compacted together, a spirit may take bodies of
various forms and by this means speak and move with strength—to him
I reply that when there are neither nerves nor bones there can be no
force exercised in any kind of movement made by such imaginary
spirits.

Beware of the teaching of these speculators, because their reasoning
is not confirmed by experience.

1213.

Of all human opinions that is to be reputed the most foolish which
deals with the belief in Necromancy, the sister of Alchemy, which
gives birth to simple and natural things. But it is all the more
worthy of reprehension than alchemy, because it brings forth nothing
but what is like itself, that is, lies; this does not happen in
Alchemy which deals with simple products of nature and whose
function cannot be exercised by nature itself, because it has no
organic instruments with which it can work, as men do by means of
their hands, who have produced, for instance, glass &c. but this
Necromancy the flag and flying banner, blown by the winds, is the
guide of the stupid crowd which is constantly witness to the
dazzling and endless effects of this art; and there are books full,
declaring that enchantments and spirits can work and speak without
tongues and without organic instruments— without which it is
impossible to speak— and can carry heaviest weights and raise
storms and rain; and that men can be turned into cats and wolves and
other beasts, although indeed it is those who affirm these things
who first became beasts.

And surely if this Necromancy did exist, as is believed by small
wits, there is nothing on the earth that would be of so much
importance alike for the detriment and service of men, if it were
true that there were in such an art a power to disturb the calm
serenity of the air, converting it into darkness and making
coruscations or winds, with terrific thunder and lightnings rushing
through the darkness, and with violent storms overthrowing high
buildings and rooting up forests; and thus to oppose armies,
crushing and annihilating them; and, besides these frightful storms
may deprive the peasants of the reward of their labours.—Now what
kind of warfare is there to hurt the enemy so much as to deprive him
of the harvest? What naval warfare could be compared with this? I
say, the man who has power to command the winds and to make ruinous
gales by which any fleet may be submerged, —surely a man who could
command such violent forces would be lord of the nations, and no
human ingenuity could resist his crushing force. The hidden
treasures and gems reposing in the body of the earth would all be
made manifest to him. No lock nor fortress, though impregnable,
would be able to save any one against the will of the necromancer.
He would have himself carried through the air from East to West and
through all the opposite sides of the universe. But why should I
enlarge further upon this? What is there that could not be done by
such a craftsman? Almost nothing, except to escape death. Hereby I
have explained in part the mischief and the usefulness, contained in
this art, if it is real; and if it is real why has it not remained
among men who desire it so much, having nothing to do with any
deity? For I know that there are numberless people who would, to
satisfy a whim, destroy God and all the universe; and if this
necromancy, being, as it were, so necessary to men, has not been
left among them, it can never have existed, nor will it ever exist
according to the definition of the spirit, which is invisible in
substance; for within the elements there are no incorporate things,
because where there is no body, there is a vacuum; and no vacuum can
exist in the elements because it would be immediately filled up.
Turn over.

1214.

We have said, on the other side of this page, that the definition of
a spirit is a power conjoined to a body; because it cannot move of
its own accord, nor can it have any kind of motion in space; and if
you were to say that it moves itself, this cannot be within the
elements. For, if the spirit is an incorporeal quantity, this
quantity is called a vacuum, and a vacuum does not exist in nature;
and granting that one were formed, it would be immediately filled up
by the rushing in of the element in which the vacuum had been
generated. Therefore, from the definition of weight, which is
this—Gravity is an accidental power, created by one element being
drawn to or suspended in another—it follows that an element, not
weighing anything compared with itself, has weight in the element
above it and lighter than it; as we see that the parts of water have
no gravity or levity compared with other water, but if you draw it
up into the air, then it would acquire weight, and if you were to
draw the air beneath the water then the water which remains above
this air would acquire weight, which weight could not sustain itself
by itself, whence collapse is inevitable. And this happens in water;
wherever the vacuum may be in this water it will fall in; and this
would happen with a spirit amid the elements, where it would
continuously generate a vacuum in whatever element it might find
itself, whence it would be inevitable that it should be constantly
flying towards the sky until it had quitted these elements.

We have proved that a spirit cannot exist of itself amid the
elements without a body, nor can it move of itself by voluntary
motion unless it be to rise upwards. But now we will say how such a
spirit taking an aerial body would be inevitably melt into air;
because if it remained united, it would be separated and fall to
form a vacuum, as is said above; therefore it is inevitable, if it
is to be able to remain suspended in the air, that it should absorb
a certain quantity of air; and if it were mingled with the air, two
difficulties arise; that is to say: It must rarefy that portion of
the air with which it mingles; and for this cause the rarefied air
must fly up of itself and will not remain among the air that is
heavier than itself; and besides this the subtle spiritual essence
disunites itself, and its nature is modified, by which that nature
loses some of its first virtue. Added to these there is a third
difficulty, and this is that such a body formed of air assumed by
the spirits is exposed to the penetrating winds, which are
incessantly sundering and dispersing the united portions of the air,
revolving and whirling amidst the rest of the atmosphere; therefore
the spirit which is infused in this