Inventors

"The outlines and form of any part of a body in light and shade are indistinct in the shadows and in the high lights; but in the portions between the light and the shadows they are highly conspicuous."

"The point, being indivisible, occupies no space. That which occupies no space is nothing. The limiting surface of one thing is the beginning of another."

"Nothing is that which fills no space. If one single point placed in a circle may be the starting point of an infinite number of lines, and the termination of an infinite number of lines, there must be an infinite number of points separable from this point, and these when reunited become one again; whence it follows that the part may be equal to the whole."

"The smallest natural point is larger than all mathematical points, and this is proved because the natural point has continuity, and any thing that is continuous is infinitely divisible; but the mathematical point is indivisible because it has no size."

"A point is not part of a line."

"The eye — which sees all objects reversed — retains the images for some time. This conclusion is proved by the results; because, the eye having gazed at light retains some impression of it. After looking (at it) there remain in the eye images of intense brightness, that make any less brilliant spot seem dark until the eye has lost the last trace of the impression of the stronger light."

"The eye which turns from a white object in the light of the sun and goes into a less fully lighted place will see everything as dark."

"Here forms, here colours, here the character of every part of the universe are concentrated to a point; and that point is so marvellous a thing … Oh! marvellous, O stupendous Necessity — by thy laws thou dost compel every effect to be the direct result of its cause, by the shortest path. These are miracles..."

"The painter who draws merely by practice and by eye, without any reason, is like a mirror which copies every thing placed in front of it without being conscious of their existence."

"Those who are in love with practice without knowledge are like the sailor who gets into a ship without rudder or compass and who never can be certain whether he is going. Practice must always be founded on sound theory, and to this Perspective is the guide and the gateway; and without this nothing can be done well in the matter of drawing."

"These rules will enable you to have a free and sound judgment; since good judgment is born of clear understanding, and a clear understanding comes of reasons derived from sound rules, and sound rules are the issue of sound experience — the common mother of all the sciences and arts. Hence, bearing in mind the precepts of my rules, you will be able, merely by your amended judgment, to criticise and recognise every thing that is out of proportion in a work, whether in the perspective or in the figures or any thing else."

"These rules are of use only in correcting the figures; since every man makes some mistakes in his first compositions and he who knows them not, cannot amend them. But you, knowing your errors, will correct your works and where you find mistakes amend them, and remember never to fall into them again. But if you try to apply these rules in composition you will never make an end, and will produce confusion in your works."

"If the Lord — who is the light of all things — vouchsafe to enlighten me, I will treat of Light; wherefore I will divide the present work into 3 Parts... Linear Perspective, The Perspective of Colour, The Perspective of Disappearance."

"Among all the studies of natural causes and reasons Light chiefly delights the beholder; and among the great features of Mathematics the certainty of its demonstrations is what preeminently (tends to) elevate the mind of the investigator. Perspective, therefore, must be preferred to all the discourses and systems of human learning. In this branch [of science] the beam of light is explained on those methods of demonstration which form the glory not so much of Mathematics as of Physics and are graced with the flowers of both."

"Many will think they may reasonably blame me by alleging that my proofs are opposed to the authority of certain men held in the highest reverence by their inexperienced judgments; not considering that my works are the issue of pure and simple experience, who is the one true mistress. These rules are sufficient to enable you to know the true from the false — and this aids men to look only for things that are possible and with due moderation — and not to wrap yourself in ignorance, a thing which can have no good result, so that in despair you would give yourself up to melancholy."

"Those men who are inventors and interpreters between Nature and Man, as compared with boasters and declaimers of the works of others, must be regarded and not otherwise esteemed than as the object in front of a mirror, when compared with its image seen in the mirror. For the first is something in itself, and the other nothingness. — Folks little indebted to Nature, since it is only by chance that they wear the human form and without it I might class them with the herds of beasts."

"Though I may not, like them, be able to quote other authors, I shall rely on that which is much greater and more worthy — on experience, the mistress of their Masters. They go about puffed up and pompous, dressed and decorated with [the fruits], not of their own labours, but of those of others. And they will not allow me my own. They will scorn me as an inventor; but how much more might they — who are not inventors but vaunters and declaimers of the works of others — be blamed."

"I know that many will call this useless work."

"Seeing that I can find no subject specially useful or pleasing — since the men who have come before me have taken for their own every useful or necessary theme — I must do like one who, being poor, comes last to the fair, and can find no other way of providing himself than by taking all the things already seen by other buyers, and not taken but refused by reason of their lesser value. I, then, will load my humble pack with this despised and rejected merchandise, the refuse of so many buyers; and will go about to distribute it, not indeed in great cities, but in the poorer towns, taking such a price as the wares I offer may be worth."

"The Book of the science of Mechanics must precede the Book of useful inventions."

"I am not to blame for putting forward, in the course of my work on science, any general rule derived from a previous conclusion."

"Mechanics is the paradise of the mathematical sciences because by means of it one comes to the fruits of mathematics."

"Human subtlety...will never devise an invention more beautiful, more simple or more direct than does nature, because in her inventions nothing is lacking, and nothing is superfluous."

"Necessity is the mistress and guardian of Nature."

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

"Iron rusts from disuse; stagnant water loses its purity and in cold weather becomes frozen; even so does inaction sap the vigor of the mind."

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

"Shun those studies in which the work that results dies with the worker."

"Tristo è quel discepolo che non avanza il suo maestro. (Modern Italian)"

"Tristo é lo discepolo che non avanza il suo maestro."

"Life well spent is long."

"As a well-spent day brings happy sleep, so life well used brings happy death."

"Let no man who is not a Mathematician read the elements of my work."

"3 miglia più in là si trova li edifici della vena del rame e dello argento, presso una terra detta Pra Santo Petro e vene di ferro e cose fantastiche. (Ancient Italian)"

"truovasi di miglio i(n) miglio bone osteriee. (Ancient Italian)"

"Subito salse in me due cose: paura e desiderio: paura per la minacciante e scura spelonca, desiderio per vedere se là entro fusse alcuna miracolosa cosa. (Ancient Italian)"

"Su per lago di Como di ver Lamagnia (Alemagna, cioè Germania) è valle di Ciavenna dove la Mera fiume mette in esso lago. Qui si truova montagni sterili e altissime chon grandi scogli ... In queste montagnie li uccielli d’acqua dette maragoni. Qui nasscie abeti, larici eppini, daini, stambuche, chamoze e teribili orsi. Non ci si pò montare se none a 4 piedi. Vannoci i villani a tempi delle nevi chon grande ingiegni per fare trabochare gli orsi giù per esse ripe. Queste montagni strette metano i(n) mezo il fiume. Sono a destra e assinistra per isspatio di miglia 20 tutti a detto modo."

"Fa vini potenti e assai, … e ‘l vino vale el più uno soldo il boccale e la libbra della vitella un soldo e ‘l sale 10 dinari, e ‘l simile il burro, ed è la loro libbra 30 once, e l’ova un soldo la soldata. (Modern Italian)"

"It is the infinite alone that cannot be attained, for if it could it would become finite."

"As a day well spent makes sleep seem pleasant, so a life well employed makes death pleasant. A life well spent is long."

"Thou, O God, sellest us all benefits, at the cost of our toil...."

"Look at the grace and sweetness of men and women in the street..."

"The painter strives and competes with nature...There is nothing in all nature without its reason. If you know the reason, you do not need the experience..."

"Oysters open completely when the moon is full; and when the crab sees one it throws a piece of stone or seaweed into it and the oyster cannot close again so that it serves the crab for meat. Such is the fate of him who opens his mouth too much and thereby puts himself at the mercy of the listener."

"Painting is poetry which is seen and not heard, and poetry is a painting which is heard but not seen. These two arts, you may call them both either poetry or painting, have here interchanged the senses by which they penetrate to the intellect."

"Light is the chaser away of darkness. Shade is the obstruction of light. Primary light is that which falls on objects and causes light and shade. And derived lights are those portions of a body which are illuminated by the primary light. A primary shadow is that side of a body on which the light cannot fall."

"Darkness is absence of light. Shadow is diminution of light."

"Shadow partakes of the nature of universal matter. All such matters are more powerful in their beginning and grow weaker towards the end, I say at the beginning, whatever their form or condition may be and whether visible or invisible. And it is not from small beginnings that they grow to a great size in time; as it might be a great oak which has a feeble beginning from a small acorn. Yet I may say that the oak is most powerful at its beginning, that is where it springs from the earth, which is where it is largest."

"A shadow may be infinitely dark, and also of infinite degrees of absence of darkness. The beginnings and ends of shadow lie between the light and darkness and may be infinitely diminished and infinitely increased. Shadow is the means by which bodies display their form. The forms of bodies could not be understood in detail but for shadow."

"Shadow is the diminution alike of light and of darkness, and stands between darkness and light."