Part 15
The representation of an object in every degree of distance, loses degrees of its strength; that is, in proportion as the object is more remote from the eye it will be less perceivable through the air in its representation.
/Chap. CCCXI./--_Of Buildings seen in a thick Air._
/That/ part of a building seen through a thick air, will appear less distinct than another part seen through a thinner air. Therefore the eye, N, looking at the tower A D, will see it more confusedly in the lower degrees, but at the same time lighter; and as it ascends to the other degrees it will appear more distinct, but somewhat darker.
/Chap. CCCXII./--_Of Towns and other Objects seen through a thick Air._
/Buildings/ or towns seen through a fog, or the air made thick by smoke or other vapours, will appear less distinct the lower they are; and, _vice versâ_, they will be sharper and more visible in proportion as they are higher. We have said, in Chapter cccxxi. that the air is thicker the lower it is, and thinner as it is higher. It is demonstrated also by the cut, where the tower, A F, is seen by the eye N, in a thick air, from B to F, which is divided into four degrees, growing thicker as they are nearer the bottom. The less the quantity of air interposed between the eye and its object is, the less also will the colour of the object participate of the colour of that air. It follows, that the greater the quantity of the air interposed between the eye and the object seen, is, the more this object will participate of the colour of the air. It is demonstrated thus: N being the eye looking at the five parts of the tower A F, viz. A B C D E, I say, that if the air were of the same thickness, there would be the same proportion between the colour of the air at the bottom of the tower and the colour of the air that the same tower has at the place B, as there is in length between the line M and F. As, however, we have supposed that the air is not of equal thickness, but, on the contrary, thicker as it is lower, it follows, that the proportion by which the air tinges the different elevations of the tower B C F, exceeds the proportion of the lines; because the line M F, besides its being longer than the line S B, passes by unequal degrees through a quality of air which is unequal in thickness.
/Chap. CCCXIII./--_Of the inferior Extremities of distant Objects._
/The/ inferior or lower extremities of distant objects are not so apparent as the upper extremities. This is observable in mountains and hills, the tops of which detach from the sides of other mountains behind. We see the tops of these more determined and distinctly than their bases; because the upper extremities are darker, being less encompassed by thick air, which always remains in the lower regions, and makes them appear dim and confused. It is the same with trees, buildings, and other objects high up. From this effect it often happens that a high tower, seen at a great distance, will appear broad at top, and narrow at bottom; because the thin air towards the top does not prevent the angles on the sides and other different parts of the tower from being seen, as the thick air does at bottom. This is demonstrated by the seventh proposition[77], which says, that the thick air interposed between the eye and the sun, is lighter below than above, and where the air is whiteish, it confuses the dark objects more than if such air were blueish or thinner, as it is higher up. The battlements of a fortress have the spaces between equal to the breadth of the battlement, and yet the space will appear wider; at a great distance the battlements will appear very much diminished, and being removed still farther, will disappear entirely, and the fort shew only the straight wall, as if there were no battlements.
/Chap. CCCXIV./--_Which Parts of Objects disappear first by being removed farther from the Eye, and which preserve their Appearance._
/The/ smallest parts are those which, by being removed, lose their appearance first; this may be observed in the gloss upon spherical bodies, or columns, and the slender parts of animals; as in a stag, the first sight of which does not discover its legs and horns so soon as its body, which, being broader, will be perceived from a greater distance. But the parts which disappear the very first, are the lines which describe the members, and terminate the surface and shape of bodies.
/Chap. CCCXV./--_Why Objects are less distinguished in proportion as they are farther removed from the Eye._
/This/ happens because the smallest parts are lost first; the second, in point of size, are also lost at a somewhat greater distance, and so on successively; the parts by degrees melting away, the perception of the object is diminished; and at last all the parts, and the whole, are entirely lost to the sight[78]. Colours also disappear on account of the density of the air interposed between the eye and the object.
/Chap. CCCXVI./--_Why Faces appear dark at a Distance._
/It/ is evident that the similitude of all objects placed before us, large as well as small, is perceptible to our senses through the iris of the eye. If through so small an entrance the immensity of the sky and of the earth is admitted, the faces of men (which are scarcely any thing in comparison of such large objects), being still diminished by the distance, will occupy so little of the eye, that they become almost imperceptible. Besides, having to pass through a dark medium from the surface to the _Retina_ in the inside, where the impression is made, the colour of faces (not being very strong, and rendered still more obscure by the darkness of the tube) when arrived at the focus appears dark. No other reason can be given on that point, except that the speck in the middle of the apple of the eye is black, and, being full of a transparent fluid like air, performs the same office as a hole in a board, which on looking into it appears black; and that those things which are seen through both a light and dark air, become confused and obscure.
/Chap. CCCXVII./--_Of Towns and other Buildings seen through a Fog in the Morning or Evening._
/Buildings/ seen afar off in the morning or in the evening, when there is a fog, or thick air, shew only those parts distinctly which are enlightened by the sun towards the horizon; and the parts of those buildings which are not turned towards the sun remain confused and almost of the colour of the fog.
/Chap. CCCXVIII./--_Of the Height of Buildings seen in a Fog._
/Of/ a building near the eye the top parts will appear more confused than the bottom, because there is more fog between the eye and the top than at the base. And a square tower, seen at a great distance through a fog, will appear narrower at the base than at the summit. This is accounted for in Chapter cccxiii. which says, that the fog will appear whiter and thicker as it approaches the ground; and as it is said before[79], that a dark object will appear smaller in proportion as it is placed on a whiter ground. Therefore the fog being whiter at bottom than at top, it follows that the tower (being darkish) will appear narrower at the base than at the summit.
/Chap. CCCXIX./--_Why Objects which are high, appear darker at a Distance than those which are low, though the Fog be uniform, and of equal Thickness._
/Amongst/ objects situated in a fog, thick air, vapour, smoke, or at a distance, the highest will be the most distinctly seen: and amongst objects equal in height, that placed in the darkest fog, will be most confused and dark. As it happens to the eye H, looking at A B C, three towers of equal height; it sees the top C as low as R, in two degrees of thickness; and the top B, in one degree only; therefore the top C will appear darker than the top of the tower B.
/Chap. CCCXX./--_Of Objects seen in a Fog._
/Objects/ seen through a fog will appear larger than they are in reality, because the aerial perspective does not agree with the linear, viz. the colour does not agree with the magnitude of the object[80]; such a fog being similar to the thickness of air interposed between the eye and the horizon in fine weather. But in this case the fog is near the eye, and though the object be also near, it makes it appear as if it were as far off as the horizon; where a great tower would appear no bigger than a man placed near the eye.
/Chap. CCCXXI./--_Of those Objects which the Eyes perceive through a Mist or thick Air._
/The/ nearer the air is to water, or to the ground, the thicker it becomes. It is proved by the nineteenth proposition of the second book[81], that bodies rise in proportion to their weight; and it follows, that a light body will rise higher than another which is heavy.
/Chap. CCCXXII./--_Miscellaneous Observations._
/Of/ different objects equal in magnitude, form, shade, and distance from the eye, those will appear the smaller that are placed on the lighter ground. This is exemplified by observing the sun when seen behind a tree without leaves; all the ramifications seen against that great light are so diminished that they remain almost invisible. The same may be observed of a pole placed between the sun and the eye.
Parallel bodies placed upright, and seen through a fog, will appear larger at top than at bottom. This is proved by the ninth proposition[82], which says, that a fog, or thick air, penetrated by the rays of the sun, will appear whiter the lower they are.
Things seen afar off will appear out of proportion, because the parts which are the lightest will send their image with stronger rays than the parts which are darkest. I have seen a woman dressed in black, with a white veil over her head, which appeared twice as large as her shoulders covered with black.
MISCELLANEOUS OBSERVATIONS.
LANDSCAPE.
/Chap. CCCXXIII./--_Of Objects seen at a Distance._
/Any/ dark object will appear lighter when removed to some distance from the eye. It follows, by the contrary reason, that a dark object will appear still darker when brought nearer to the eye. Therefore the inferior parts of any object whatever, placed in thick air, will appear farther from the eye at the bottom than at the top; for that reason the lower parts of a mountain appear farther off than its top, which is in reality the farthest.
/Chap. CCCXXIV./--_Of a Town seen through a thick Air._
/The/ eye which, looking downwards, sees a town immersed in very thick air, will perceive the top of the buildings darker, but more distinct than the bottom. The tops detach against a light ground, because they are seen against the low and thick air which is beyond them. This is a consequence of what has been explained in the preceding chapter.
/Chap. CCCXXV./--_How to draw a Landscape._
/Contrive/ that the trees in your landscape be half in shadow and half in the light. It is better to represent them as when the sun is veiled with thin clouds, because in that case the trees receive a general light from the sky, and are darkest in those parts which are nearest to the earth.
/Chap. CCCXXVI./--_Of the Green of the Country._
/Of/ the greens seen in the country, that of trees and other plants will appear darker than that of fields and meadows, though they may happen to be of the same quality.
/Chap. CCCXXVII./--_What Greens will appear most of a blueish Cast._
/Those/ greens will appear to approach nearest to blue which are of the darkest shade when remote. This is proved by the seventh proposition[83], which says, that blue is composed of black and white seen at a great distance.
/Chap. CCCXXVIII./--_The Colour of the Sea from different Aspects._
/When/ the sea is a little ruffled it has no sameness of colour; for whoever looks at it from the shore, will see it of a dark colour, in a greater degree as it approaches towards the horizon, and will perceive also certain lights moving slowly on the surface like a flock of sheep. Whoever looks at the sea from on board a ship, at a distance from the land, sees it blue. Near the shore it appears darkish, on account of the colour of the earth reflected by the water, as in a looking-glass; but at sea the azure of the air is reflected to the eye by the waves in the same manner.
/Chap. CCCXXIX./--_Why the same Prospect appears larger at some Times than at others._
/Objects/ in the country appear sometimes larger and sometimes smaller than they actually are, from the circumstance of the air interposed between the eye and the horizon, happening to be either thicker or thinner than usual.
Of two horizons equally distant from the eye, that which is seen through the thicker air will appear farther removed; and the other will seem nearer, being seen through a thinner air.
Objects of unequal size, but equally distant, will appear equal if the air which is between them and the eye be of proportionable inequality of thickness, viz. if the thickest air be interposed between the eye and the smallest of the objects. This is proved by the perspective of colours[84], which is so deceitful that a mountain which would appear small by the compasses, will seem larger than a small hill near the eye; as a finger placed near the eye will cover a large mountain far off.
/Chap. CCCXXX./--_Of Smoke._
/Smoke/ is more transparent, though darker towards the extremities of its waves than in the middle.
It moves in a more oblique direction in proportion to the force of the wind which impels it.
Different kinds of smoke vary in colour, as the causes that produce them are various.
Smoke never produces determined shadows, and the extremities are lost as they recede from their primary cause. Objects behind it are less apparent in proportion to the thickness of the smoke. It is whiter nearer its origin, and bluer towards its termination.
Fire appears darker, the more smoke there is interposed between it and the eye.
Where smoke is farther distant, the objects are less confused by it.
It encumbers and dims all the landscape like a fog. Smoke is seen to issue from different places, with flames at the origin, and the most dense part of it. The tops of mountains will be more seen than the lower parts, as in a fog.
/Chap. CCCXXXI./--_In what Part Smoke is lightest._
/Smoke/ which is seen between the sun and the eye will be lighter and more transparent than any other in the landscape. The same is observed of dust, and of fog; while, if you place yourself between the sun and those objects, they will appear dark.
/Chap. CCCXXXII./--_Of the Sun-beams passing through the Openings of Clouds._
/The/ sun-beams which penetrate the openings interposed between clouds of various density and form, illuminate all the places over which they pass, and tinge with their own colour all the dark places that are behind: which dark places are only seen in the intervals between the rays.
/Chap. CCCXXXIII./--_Of the Beginning of Rain._
/When/ the rain begins to fall, it tarnishes and darkens the air, giving it a dull colour, but receives still on one side a faint light from the sun, and is shaded on the other side, as we observe in clouds; till at last it darkens also the earth, depriving it entirely of the light of the sun. Objects seen through the rain appear confused and of undetermined shape, but those which are near will be more distinct. It is observable, that on the side where the rain is shaded, objects will be more clearly distinguished than where it receives the light; because on the shady side they lose only their principal lights, whilst on the other they lose both their lights and shadows, the lights mixing with the light part of the rain, and the shadows are also considerably weakened by it.
/Chap. CCCXXXIV./--_The Seasons are to be observed._
/In/ Autumn you will represent the objects according as it is more or less advanced. At the beginning of it the leaves of the oldest branches only begin to fade, more or less, however, according as the plant is situated in a fertile or barren country; and do not imitate those who represent trees of every kind (though at equal distance) with the same quality of green. Endeavour to vary the colour of meadows, stones, trunks of trees, and all other objects, as much as possible, for Nature abounds in variety _ad infinitum_.
/Chap. CCCXXXV./--_The Difference of Climates to be observed._
/Near/ the sea-shore, and in southern parts, you will be careful not to represent the Winter season by the appearance of trees and fields, as you would do in places more inland, and in northern countries, except when these are covered with ever-greens, which shoot afresh all the year round.
/Chap. CCCXXXVI./--_Of Dust._
/Dust/ becomes lighter the higher it rises, and appears darker the less it is raised, when it is seen between the eye and the sun.
/Chap. CCCXXXVII./--_How to represent the Wind._
/In/ representing the effect of the wind, besides the bending of trees, and leaves twisting the wrong side upwards, you will also express the small dust whirling upwards till it mixes in a confused manner with the air.
/Chap. CCCXXXVIII./--_Of a Wilderness._
/Those/ trees and shrubs which are by their nature more loaded with small branches, ought to be touched smartly in the shadows, but those which have larger foliage, will cause broader shadows.
/Chap. CCCXXXIX./--_Of the Horizon seen in the Water._
/By/ the sixth proposition[85], the horizon will be seen in the water as in a looking-glass, on that side which is opposite the eye. And if the painter has to represent a spot covered with water, let him remember that the colour of it cannot be either lighter or darker than that of the neighbouring objects.
/Chap. CCCXL./--_Of the Shadow of Bridges on the Surface of the Water._
/The/ shadows of bridges can never be seen on the surface of the water, unless it should have lost its transparent and reflecting quality, and become troubled and muddy; because clear water being polished and smooth on its surface, the image of the bridge is formed in it as in a looking-glass, and reflected in all the points situated between the eye and the bridge at equal angles; and even the air is seen under the arches. These circumstances cannot happen when the water is muddy, because it does not reflect the objects any longer, but receives the shadow of the bridge in the same manner as a dusty road would receive it.
/Chap. CCCXLI./--_How a Painter ought to put in Practice the Perspective of Colours._
/To/ put in practice that perspective which teaches the alteration, the lessening, and even the entire loss of the very essence of colours, you must take some points in the country at the distance of about sixty-five yards[86] from each other; as trees, men, or some other remarkable objects. In regard to the first tree, you will take a glass, and having fixed that well, and also your eye, draw upon it, with the greatest accuracy, the tree you see through it; then put it a little on one side, and compare it closely with the natural one, and colour it, so that in shape and colour it may resemble the original, and that by shutting one eye they may both appear painted, and at the same distance. The same rule may be applied to the second and third tree at the distance you have fixed. These studies will be very useful if managed with judgment, where they may be wanted in the offscape of a picture. I have observed that the second tree is less by four fifths than the first, at the distance of thirteen yards.
/Chap. CCCXLII./--_Various Precepts in Painting._
/The/ superficies of any opake body participates of the colour of the transparent medium interposed between the eye and such body, in a greater or less degree, in proportion to the density of such medium and the space it occupies.
The outlines of opake bodies will be less apparent in proportion as those bodies are farther distant from the eye.
That part of the opake body will be the most shaded, or lightest, which is nearest to the body that shades it, or gives it light.
The surface of any opake body participates more or less of the colour of that body which gives it light, in proportion as the latter is more or less remote, or more or less strong.
Objects seen between lights and shadows will appear to have greater relievo than those which are placed wholly in the light, or wholly in shadow.
When you give strength and precision to objects seen at a great distance, they will appear as if they were very near. Endeavour that your imitation be such as to give a just idea of distances. If the object in nature appear confused in the outlines, let the same be observed in your picture.
The outlines of distant objects appear undetermined and confused, for two reasons: the first is, that they come to the eye by so small an angle, and are therefore so much diminished, that they strike the sight no more than small objects do, which though near can hardly be distinguished, such as the nails of the fingers, insects, and other similar things: the second is, that between the eye and the distant objects there is so much air interposed, that it becomes thick; and, like a veil, tinges the shadows with its own whiteness, and turns them from a dark colour to another between black and white, such as azure.
Although, by reason of the great distance, the appearance of many things is lost, yet those things which receive the light from the sun will be more discernible, while the rest remain enveloped in confused shadows. And because the air is thicker near the ground, the things which are lower will appear confused; and _vice versâ_.
When the sun tinges the clouds on the horizon with red, those objects which, on account of their distance, appear blueish, will participate of that redness, and will produce a mixture between the azure and red, which renders the prospect lively and pleasant; all the opake bodies which receive that light will appear distinct, and of a reddish colour, and the air, being transparent, will be impregnated with it, and appear of the colour of lilies[87].
The air which is between the earth and the sun when it rises or sets, will always dim the objects it surrounds, more than the air any where else, because it is whiter.
It is not necessary to mark strongly the outlines of any object which is placed upon another. It ought to detach of itself.
If the outline or extremity of a white and curved surface terminate upon another white body, it will have a shade at that extremity, darker than any part of the light; but if against a dark object, such outline, or extremity, will be lighter than any part of the light.
Those objects which are most different in colour, will appear the most detached from each other.
Those parts of objects which first disappear in the distance, are extremities similar in colour, and ending one upon the other, as the extremities of an oak tree upon another oak similar to it. The next to disappear at a greater distance are, objects of mixed colours, when they terminate one upon the other, as trees, ploughed fields, walls, heaps of rubbish, or of stones. The last extremities of bodies that vanish are those which, being light, terminate upon a dark ground; or being dark, upon a light ground.
Of objects situated above the eye, at equal heights, the farthest removed from the eye will appear the lowest; and if situated below the eye, the nearest to it will appear the lowest. The parallel lines situated sidewise will concur to one point[88].
Those objects which are near a river, or a lake, in the distant part of a landscape, are less apparent and distinct than those that are remote from them.
Of bodies of equal density, those that are nearest to the eye will appear thinnest, and the most remote thickest.