'Iron rusts from disuse, stagnant water loses its purity and in cold weather becomes frozen; even so does inaction sap the vigour of the mind! 

Whoever in discussion adduces authority uses not intellect but rather memory. 

Good literature proceeds from men of natural probity, and since one ought rather to praise the inception than the result, you should give
greater praise to a man of probity unskilled in letters than to one skilled in letters but devoid of probity. c.a. 76 r. a 

As courage endangers life even so fear preserves it. 

Threats only serve as weapons to the threatened. 

Who walks rightly seldom falls. 

You do ill if you praise but worse if you censure what you do not rightly understand. c.a. 76 v. a 

To devise is the work of the master, to execute the act of the servant. 
He who has most possessions should have the greatest fear of loss. c.a. 109 v. a 

The natural desire of good men is knowledge. c.a. 119 v. a 

Aristotle says that everything desires to keep its own nature. c.a. 123 r. a 

A thing that moves acquires as much space as it loses, c.a. 152 v. a 

Who goes not ever in fear sustains many injuries and often repents. c.a. 170 r. b 

The acquisition of any knowledge whatever is always useful to the intellect, because it will be able to banish the useless things and retain
those which are good. For nothing can be either loved or hated unless it is first known. c.a. 226 v. b 



Inequality is the cause of all local movements. 

There is no rest without equality. c.a. 288 v. a 

The words freeze in your mouth and you will make ice on Mount Etna. 

Iron rusts from disuse; stagnant water loses its purity and in cold weather becomes frozen; even so does inaction sap the vigour of the mind. c.a. 289 v. c 

Happy is that estate which is seen by the eye of its lord. 

Love conquers everything. 

This by experience is proved, that he who never puts his trust in any man will never be deceived. c.a. 344 r. b 

The instruments of swindlers are the seed of human revilings against the gods. c.a. 358 v. a 



Everything comes from everything, and everything is made out of everything, and everything returns into everything, because whatever exists in the elements is made out of these elements. c.a. 385 v. c 

Savage is he who saves himself. Tr. 1 a 

Folly is the buckler of shame as importunity is of poverty. 

Tr. 52 a

Truth brings it here to pass that falsehood afflicts the lying tongues. 

f cover 2 r. 

The memory of benefits is frail as against ingratitude. 

Reprove a friend in secret but praise him before others. 
He who walks in fear of dangers will not perish in consequence thereof. 
Lie not about the past. h 16 v. 

[Concerning fame] 
Nothing is more to be feared than ill fame. 
Toil flees away bearing in its arms fame almost hidden, h 17 v. 





Lust is the cause of generation. 

Appetite is the stay of life. 

Fear or timidity is the prolongation of life. 

Deceit is the preservation of the instrument. h 32 r. 

Moderation curbs all the vices. 

The ermine would rather die than soil itself. 


The cock does not crow until he has flapped his wings three times. 
The parrot passing from branch to branch never puts his foot where he has not first fixed his beak. 

Vows begin when hope dies. 

Movement tends towards the centre of gravity. h 48 v. 

[With drawings] 
To take away pain. 

To know better the direction of the winds. 
From a light thing there proceeds a great ruin. h 100 [43 v.] r. 

It is by testing that we discern fine gold. 

As is the mould so will the cast be. h 100 [43 r.] v. 

He who strips the wall bare on him will it fall. 
He who cuts the tree down on him will it take vengeance in its fall. 
Let the traitor avoid death: other punishments if he undergo them do not mark him. h 118 [25 v.] r. 

Ask counsel of him who governs himself well. 

Justice requires power, intelligence and will. It resembles the queen bee. 

He who neglects to punish evil sanctions the doing thereof. 
He who takes the snake by the tail is afterwards bitten by it. 
He who digs the pit upon him will it fall in ruin, h 118 [25 r.] v. 

Whoso curbs not lustful desires puts himself on a level with the beasts. 

You can have neither a greater nor a less dominion than that over yourself. 



He who thinks little makes many mistakes. 

It is easier to resist at the beginning than at the end. 

No counsel is more trustworthy than that which is given upon ships that are in peril. 

Let him expect disaster who shapes his course on a young man's counsel. h 119 [24 r.] v. 

Think well to the end, consider the end first. h 139 [4 r.] v. 

Fear springs to life more quickly than anything else. l 90 v. 

He who injures others does not safeguard himself. m 4 v. 

Give to your master the example of the captain, for it is not he who conquers but the soldiers by means of his counsel and yet he deserves
the reward. Forster 11 15 v. 

It is as great an error to speak well of a worthless man as to speak ill of a good man. Forster 11 41 v. 

Necessity is the mistress and guardian of nature. 
Necessity is the theme and artificer of nature — the bridle, the law 7 , and the theme. Forster in 43 v. 

Poor is the pupil who does not surpass his master. Forster in 66 v. 

[Sketch — head of old woman] 
In life beauty perishes and does not endure. 1 Forster in 72 r. 

Dust makes damage. Quaderni in 10 v. 

1 The text of this sentence Cosa bella mortal passa e non dura as has been pointed out by Sir Eric Maclagan in a letter in The Times Literary Supplement (March 8th, 1923) 
occurs as a line in a sonnet of Petrarch: 'Chi vuol veder quantunque puo Natura', No. exc, line 8. 

In the former edition of Leonardo's Notebooks I translated this sentence as 'in life beauty perishes, not in art', having in my reading of the text followed Dr. Richter in
supposing the last word to be 'dart' for 'd'arte'. A further examination of a photograph of the page kindly supplied to me by Sir Eric Maclagan has convinced me of my error. 

It is in the erroneous form cosa bella mortal passa e non d'arte which originated merely in an error of transcription that the sentence occurs on the title-page of
d'Annunzio's tragedy La Gioconda. 



The heavy cannot be created without it being joined with the light and together they destroy each other. Quaderni in 12 r. 

\Studies of emblems with mottoes] 

Obstacles cannot bend me. 

Every obstacle yields to effort. 

Not to leave the furrow. 

He who fixes his course by a star changes not. 

Windsor: Drawings 12282 r. 
[ Drawings of same] 
Persistent effort. 
Predetermined effort. 
He is not turned who is fixed to such a star. 

Windsor: Drawings 12701 

May I be deprived of movement ere I weary of being useful. 

Movement will fail sooner than usefulness. 

Death rather than weariness. 

I never weary in being useful. I am not tired of serving others. 

I weary not in welldoing is a motto for carnival. 

Without fatigue. 

No labour suffices to tire me. 

Hands into which fall like snow ducats and precious stones, these never tire of serving, but such service is only for its usefulness and not
for our own advantage. 

I never weary of being useful. 

Naturally nature has so fashioned me. Windsor: Drawings 12700 r. 

He who wishes to become rich in a day is hanged in a year. 

Windsor: Drawings 12351 r.