Chapter XVII: Part VI (3)

"We can scarcely ever say that the surface of illumined
bodies exhibits the real colour of those bodies. Take a
white band and place it in the dark, and let it receive
light by means of three apertures from the sun, from fire,
and from the sky: the white band will be tricoloured."[19]

Aristotle.

"When the light falls on any object and assumes (for
example) a red or green tint, it is again reflected on other
substances, thus undergoing a new change. But this effect,
though it really takes place, is not appreciable by the
eye: though the light thus reflected to the eye is composed
of a variety of colours, the principal of these only are
distinguishable."

Leonardo.

"No colour reflected on the surface of another colour,
tinges that surface with its own colour (merely), but will
be mixed with various other reflections impinging on the
same surface:" but such effects, he observes elsewhere, "are
scarcely, if at all, distinguishable in a very diffused
light."[20]

Aristotle.

"Thus, all combinations of colours are owing to three
causes: the light, the medium through which the light
appears, such as water or air, and lastly the local colour
from which the light happens to be reflected."

Leonardo.

"All illumined objects partake of the colour of the light
they receive.

"Every opaque surface partakes of the colour of the
intervening transparent medium, according to the density of
such medium and the distance between the eye and the object.

"The medium is of two kinds; either it has a surface, like
water, &c., or it is without a common surface, like the
air."[21]

In the observations on trees and plants more points of resemblance might be quoted; the passages corresponding with Goethe's views are much more numerous.

It is remarkable that Leonardo, in opposition, it seems to some authorities,[22] agrees with Aristotle in reckoning black and white as colours, placing them at the beginning and end of the scale.[23] Like Aristotle, again, he frequently makes use of the term black, for obscurity; he even goes further, for he seems to consider that blue may be produced by the actual mixture of black and white, provided they are pure.[24] The ancient author, however, explains himself on this point as follows--"We must not attempt to make our observations on these effects by mixing colours as painters mix them, but by remarking the appearances as produced by the rays of light mingling with each other."[25]

When we consider that Leonardo's Treatise professes to embrace the subject of imitation in painting, and that Aristotle's briefly examines the physical nature and appearance of colours, it must be admitted that the latter sustains the above comparison with advantage; and it is somewhat extraordinary that observations indicating so refined a knowledge of nature, as regards the picturesque, should not have been taken into the account, for such appears to be the fact, in the various opinions and conjectures that have been expressed from time to time on the painting of the Greeks. The treatise in question must have been written when Apelles painted, or immediately before; and as a proof that Aristotle's remarks on the effect of semi-transparent mediums were not lost on the artists of his time, the following passage from Pliny is subjoined, for, though it is well known, it acquires additional interest from the foregoing extracts.

"He (Apelles) passed a dark colour over his pictures when finished, so thin that it increased the splendour of the tints, while it protected the surface from dust and dirt: it could only be seen on looking into the picture. The effect of this operation, judiciously managed, was to prevent the colours from being too glaring, and to give the spectator the impression of looking through a transparent crystal. At the same time it seemed almost imperceptibly to add a certain dignity of tone to colours that were too florid." "This," says Reynolds, "is a true and artist-like description of glazing or scumbling, such as was practised by Titian and the rest of the Venetian painters."

The account of Pliny has, in this instance, internal evidence of truth, but it is fully confirmed by the following passage in Aristotle:--"Another mode in which the effect of colours is exhibited is when they appear through each other, as painters employ them when they glaze (ἐπαλειφοντες)[26] a (dark) colour over a lighter one; just as the sun, which is in itself white, assumes a red colour when seen through darkness and smoke. This operation also ensures a variety of colours, for there will be a certain ratio between those which are on the surface and those which are in depth."--_De Sensu et Sensili_.

Aristotle's notion respecting the derivation of colours from white and black may perhaps be illustrated by the following opinion on the very similar theory of Goethe.

"Goethe and Seebeck regard colour as resulting from the mixture of white and black, and ascribe to the different colours a quality of darkness (σκιερὸν), by the different degrees of which they are distinguished, passing from white to black through the gradations of yellow, orange, red, violet, and blue, while green appears to be intermediate again between yellow and blue. This remark, though it has no influence in weakening the theory of colours proposed by Newton, is certainly correct, having been confirmed experimentally by the researches of Herschell, who ascertained the relative intensity of the different coloured rays by illuminating objects under the microscope by their means, &c.

"Another certain proof of the difference in brightness of the different coloured rays is afforded by the phenomena of ocular spectra. If, after gazing at the sun, the eyes are closed so as to exclude the light, the image of the sun appears at first as a luminous or white spectrum upon a dark ground, but it gradually passes through the series of colours to black, that is to say, until it can no longer be distinguished from the dark field of vision; and the colours which it assumes are successively those intermediate between white and black in the order of their illuminating power or brightness, namely, yellow, orange, red, violet, and blue. If, on the other hand, after looking for some time at the sun we turn our eyes towards a white surface, the image of the sun is seen at first as a black spectrum upon the white surface, and gradually passes through the different colours from the darkest to the lightest, and at last becomes white, so that it can no longer be distinguished from the white surface"[27]--See par 40, 44.

It is not impossible that Aristotle's enumeration of the colours may have been derived from, or confirmed by, this very experiment. Speaking of the after-image of colours he says, "The impression not only exists in the sensorium in the act of perceiving, but remains when the organ is at rest. Thus if we look long and intently on any object, when we change the direction of the eyes a responding colour follows. If we look at the sun, or any other very bright object, and afterwards shut our eyes, we shall, as if in ordinary vision, first see a colour of the same kind; this will presently be changed to a red colour, then to purple, and so on till it ends in black and disappears."--_De Insomniis_.

[1] "Geschichte der Farbenlehre," in the "Nachgelassene Werke." Cotta, 1833.

[2] The treatise in question is ascribed by Goethe to Theophrastus, but it is included in most editions of Aristotle, and even attributed to him in those which contain the works of both philosophers; for instance, in the Aldine Princeps edition, 1496. Calcagnini says, the treatise is made up of two separate works on the subject, both by Aristotle.

[3] His authority seems to have been equally great on subjects connected with the phenomena of vision; the Italian translator of a Latin treatise, by Portius, on the structure and colours of the eye, thus opens his dedication to the Cardinal Ercole Gonzaga, of Mantua:--"Grande anzi quasi infinito è l'obligo che ha il mondo con quel più divino che umano spirito di Aristotile."

[4] In a letter to Ziegler the mathematician, Calcagnini speaks of Raphael as "the first of painters in the theory as well as in the practice of his art." This expression may, however, have had reference to a remarkable circumstance mentioned in the same letter, namely, that Raphael entertained the learned Fabius of Ravenna as a constant guest, and employed him to translate Vitruvius into Italian. This MS. translation, with marginal notes, written by Raphael, is now in the library at Munich. "Passavant, Rafael von Urbino."

[5] Lodovico Dolce's Treatise on Colours (1565) is in the form of a dialogue, like his "Aretino." The abridged theory of Aristotle is followed by a translation of the Treatise of Antonius Thylesius on Colours; this is adapted to the same colloquial form, and the author is not acknowledged: the book ends with an absurd catalogue of emblems. The "Somma della Filosofia d'Aristotile," published earlier by the same author, is a very careless performance.

[6] A Latin translation of Aristotle's Treatise on Colours, with comments by Simon Portius, was first published, according to Goethe, at Naples in 1537. In a later Florentine edition, 1548, dedicated to Cosmo I., Portius alludes to his having lectured at an earlier period in Florence on the doctrines of Aristotle, at which time he translated the treatise in question. Another Latin translation, with notes, was published later in the same century at Padua--"Emanuele Marguino Interprete:" but by far the clearest view of the Aristotelian theory is to be found in the treatise of Antonio Vidi Scarmiglione of Fuligno ("De Coloribus," Marpurgi, 1591). It is dedicated to the Emperor Rudolph II. Of all the paraphrases of the ancient doctrine this comes nearest to the system of Goethe; but neither this nor any other of the works alluded to throughout this Note are mentioned by the author in his History of the Doctrine of Colours, except that of Portius.

[7] An earlier Italian translation appeared in Rome, 1535. See "Argelatus Biblioteca degli Volgarizzatori."

[8] "Della Pittura e della Statua," Lib. I, p. 16, Milan edition, 1804. Compare with the "Trattato della Pittura," p. 141. Other points of resemblance are to be met with. The notion of certain colours appropriated to the four elements, occurs in Aristotle, and is indeed attributed to older writers.

[9] See the notes to the Roman edition of the "Trattato della Pittura."

[10] Page 237.

[11] Page 301.

[12] In the Treatise _De Igne_, by Theophrastus, we find the same notion thus expressed: "Brightness (_τὸ λευκὸν_) seen through a dark coloured medium (_διὰ του μέλανος_) appears red; as the sun seen through smoke or soot: hence the coal is redder than the flame." Scarmiglione, from whom Kircher seems to have copied, observes:--"Itaque color realis est lux opaca; licet id e plurimis apparentiis colligere. Luna enim in magnâ solis eclipsi rubra conspicitur, quia tenebris lux præpeditur ac veluti tegitur."--_De Coloribus_.

[13] Page 122.

[14] _Τὰ ἂνθη_: translated _flores_ by Calcagnini and the rest, by Goethe, _die Blüthe_, the bloom. That the word sometimes signified pigments is sufficiently apparent from the following passage of Suidas (quoted by Emeric David, "Discours Historiques sur la Peinture Moderne") _ἂνθεσι κεκοσμημέναι, οἶον ψιμμιωίῳ φύκει καὶ τοῖς ὸμοίοις_. Variis pigmentis ornatæ, ut cerussâ, fuco, et aliis similibus. (Suid. in voc. _Ἐξμηθισμένας_.) A panel prepared for painting, with a white ground consolidated with wax, and perhaps mastic, was found in Herculaneum.

[15] Page 114.

[16] _Ἐν βάθει δὲ θεωρουμίνου ιγγυτάτω φαίνεται τῶ χρώματι κυανονοειδὴς διὰ τὴν ὰραιότητα._ "But when seen in depth, it appears (even) in its nearest colour, blue, owing to its thinness." The Latin interpretations vary very much throughout. The point which is chiefly important is however plain enough, viz. that darkness seen through a light medium is blue.

[17] Page 136-430.

[18] Page 121, 306, 326, 387.

[19] Page 306.

[20] Page 104, 369.

[21] Page 236, 260, 328.

[22] "De' semplici colori il primo è il bianco: beuchè i filosofi non accettano nè il bianco nè il nero nel numero de' colori."--p. 125, 141. Elsewhere, however, he sometimes adopts the received opinion.

[23] Leon Battista Alberti, in like manner observes:--"Affermano (i filosofi) che le spezie de' colori sono sette, cioè, che il bianco ed il nero sono i duoi estremi, infra i quali ve n'è uno nel mezzo (rosso) e che infra ciascuno di questi duoi estremi e quel del mezzo, da ogni parte ve ne sono due altri." An absurd statement of Lomazzo, p. 190, is copied verbatim from Lodovico Dolce (Somma della Filos. d'Arist.); but elsewhere, p. 306, Lomazzo agrees with Alberti. Aristotle seems to have misled the two first, for after saying there are seven colours, he appears only to mention six: he says--"There are seven colours, if brown is to be considered equivalent to black, which seems reasonable. Yellow, again, may be said to be a modification of white. Between these we find red, purple, green, and blue."--_De Sensu et Sensili_. Perhaps it is in accordance with this passage that Leonardo da Vinci reckons eight colours.--_Trattato_, p. 126.

[24] Page 122, 142, 237.

[25] On the authority of this explanation the word μιλάν has sometimes been translated in the foregoing extracts _obscurity, darkness_.

Raffaello Borghini, in his attempt to describe the doctrine of Aristotle with a view to painting, observes--"There are two principles which concur in the production of colour, namely, light and transparence." But he soon loses this clue to the best part of the ancient theory, and when he has to speak of the derivation of colours from white and black, he evidently understands it in a mere atomic sense, and adds--"I shall not at present pursue the opinion of Aristotle, who assumes black and white as principal colours, and considers all the rest as intermediate between them."--_Il Riposo_, 1. ii. Accordingly, like Lodovico Dolce, he proceeds to a subject where he was more at home, namely, the symbolical meaning of colours.

[26] This word is only strictly applied to unctuous substances, and may confirm the views of those writers who have conjectured that asphaltum was a chief ingredient in the _atramentum_ of the ancients.

[27] "Elements of Physiology," by J. Müller, M.D., translated from the German by William Baly, M.D. London, 1839.

NOTE N.--Par. 246.

"The appearance of white in the centre, according to the Newtonian theory, arises from each line of rays forming its own spectrum. These spectra, superposing each other on all the middle part, leave uncorrected (unneutralised) colours only at the two edges."--S. F.[1]

[1] This was objected to Goethe when his "Beyträge sur Optik" first appeared; he answered the objection by a coloured diagram in the plates to the "Farbenlehre:" in this he undertakes to show that the assumed gradual "correction" of the colours would produce results different from the actual appearance in nature.

NOTE O.--Par. 252.

These experiments with grey objects, which exhibit different colours as they are on dark or light grounds, were suggested, Goethe tells us, by an observation of Antonius Lucas, of Lüttich, one of Newton's opponents, and, in the opinion of the author, one of the few who made any well-founded objections. Lucas remarks, that the sun acts merely as a circumscribed image in the prismatic experiments, and that if the same sun had a lighter background than itself, the colours of the prism would be reversed. Thus in Goethe's experiments, when the grey disk is on a dark ground, it is edged with blue on being magnified; when on a light ground it is edged with yellow. Goethe acknowledges that Lucas had in some measure anticipated his own theory.--Vol. ii. p. 440.

NOTE P.--Par. 284.

The earnestness and pertinacity with which Goethe insisted that the different colours are not subject to different degrees of refrangibility are at least calculated to prove that he was himself convinced on the subject, and, however extraordinary it may seem, his conviction appears to have been the result of infinite experiments and the fullest ocular evidence. He returns to the question in the controversial division of his work, in the historical part, and again in the description of the plates. In the first he endeavours to show that Newton's experiment with the blue and red paper depends entirely on the colours being so contrived as to appear elongated or curtailed by the prismatic borders. "If," he says, "we take a light-blue instead of a dark one, the illusion (in the latter case) is at once evident. According to the Newtonian theory the yellow-red (red) is the least refrangible colour, the violet the most refrangible. Why, then, does Newton place a blue paper instead of a violet next the red? If the fact were as he states it, the difference in the refrangibility of the yellow-red and violet would be greater than in the case of the yellow-red and blue. But here comes in the circumstance that a violet paper conceals the prismatic borders less than a dark-blue paper, as every observer may now easily convince himself," &c.--Polemischer Theil, par. 45. Desaguliers, in repeating the experiment, confessed that if the ground of the colours was not black, the effect did not take place so well. Goethe adds, "not only not so well, but not at all."--Historischer Theil, p. 459. Lucas of Lüttich, one of Newton's first opponents, denied that two differently-coloured silks are different in distinctness when seen in the microscope. Another experiment proposed by him, to show the unsoundness of the doctrine of various refrangibility, was the following:--Let a tin plate painted with the prismatic colours in stripes be placed in an empty cubical vessel, so that from the spectator's point of view the colours may be just hidden by the rim. On pouring water into this vessel, all the colours become visible in the same degree; whereas, it was contended, if the Newtonian doctrine were true, some colours would be apparent before others.--Historischer Theil, p. 434.

Such are the arguments and experiments adduced by Goethe on this subject; they have all probably been answered. In his analysis of Newton's celebrated _Experimentum Crucis_, he shows again that by reversing the prismatic colours (refracting a dark instead of a light object), the colours that are the most refrangible in Newton's experiment become the least so, and _vice versâ_.

Without reference to this objection, it is now admitted that "the difference of colour is not a test of difference of refrangibility, and the conclusion deduced by Newton is no longer admissible as a general truth, that to the same degree of refrangibility ever belongs the same colour, and to the same colour ever belongs the same degree of refrangibility."--Brewster's Optics, p. 72.

NOTE Q--Par. 387.

With the exception of two very inconclusive letters to Sulpice Boisserée, and some incidental observations in the conclusion of the historical portion under the head of entoptic colours, Goethe never returned to the rainbow. Among the plates he gave the diagram of Antonius de Dominis. An interesting chapter on halos, parhelia, and paraselenæ, will be found in Brewster's Optics, p. 270.

NOTE R.--Par. 478.

The most complete exhibition of the colouring or mantling of metals was attained by the late Cav. Nobili, professor of physical science in Florence. The general mode in which these colours are produced is thus explained by him:[1]--

"A point of platinum is placed vertically at the distance of about half a line above a lamina of the same metal laid horizontally at the bottom of a vessel of glass or porcelain. Into this vessel a solution of acetate of lead is poured so as to cover not only the lamina of platinum, but two or three lines of the point as well. Lastly, the point is put in communication with the negative pole of a battery, and the lamina with the positive pole. At the moment in which the circuit is completed a series of coloured rings is produced on the lamina under the point similar to those observed by Newton in lenses pressed together."

The scale of colours thus produced corresponds very nearly with that observed by Newton and others in thin plates and films, but it is fuller, for it extends to forty-four tints. The following list, as given by Nobili, is divided by him into four series to agree with those of Newton: the numbers in brackets are those of Newton's scale. The Italian terms are untranslated, because the colours in some cases present very delicate transitions.[2]

_First Series._

1. Biondo argentino (4).[3] 6. Fulvo acceso.
2. Biondo. 7. Rosso di rame (6).
3. Biondo d'oro. 8. Ocria.
4. Biondo acceso (5). 9. Ocria violacea.
5. Fulvo. 10. Rosso violaceo (7).

Second Series.

11. Violetto (8). 20. Giallo acceso.
12. Indaco (10). 21. Giallo-rancio.
13. Blu carico. 22. Rancio (13).
14. Blu. 23. Rancio-rossiccio.
15. Blu chiaro (11) 24. Rancio-rosso.
16. Celeste. 25. Rosso-rancio.
17. Celeste giallognolo. 26. Lacca-rancia (14).
18. Giallo chiarissimo (12). 27. Lacca.
19. Giallo. 28. Lacca accesa (15).

Third Series.

29. Lacca-purpurea (16). 34. Verde-giallo (20).
30. Lacca-turchiniccia (17). 35. Verde-rancio.
31. Porpora-verdognola (18). 36. Rancio-verde (21).
32. Verde (19). 37. Rancio-roseo.
33. Verde giallognolo. 38. Lacca-rosea (22).

Fourth Series.

39. Lacca-violacea (24). 43. Verde-giallo rossiccio (28).
40. Violaceo-verdognolo (25). 44. Lacca-rosea (30).
41. Verde (26).
42. Verde-giallo (27).

"These tints," Professor Nobili observes, "are disposed according to the order of the thin mantlings which occasion them; the colour of the thinnest film is numbered 1; then follow in order those produced by a gradual thickening of the medium. I cannot deceive myself in this arrangement, for the thin films which produce the colours are all applied with the same electro-chemical process. The battery, the solution, the distances, &c., are always the same; the only difference is the time the effect is suffered to last. This is a mere instant for the colour of No. 1, a little longer for No. 2, and so on, increasing for the succeeding numbers. Other criterions, however, are not wanting to ascertain the place to which each tint belongs."

The scale differs from that of Newton, inasmuch as there is no blue in Nobili's first series and no green in the second: green only appears in the third and fourth series. "The first series," says the Professor, "is remarkable for the fire and metallic appearance of its tints, the second for clearness and brilliancy, the third and fourth for force and richness." The fourth, he observes, has the qualities of the third in a somewhat lesser degree, but the two greens are very nearly alike.

It is to be observed, that red and green are the principal ingredients in the third and fourth series, blue and yellow in the second and first.

[1] See "Memorie ed Osservazioni, edite et inedite del Cav. Professor Nobili," Firenze, 1834.

[2] The colours in some of the compound terms are in a manner mutually neutralising; such terms might, no doubt, be amended.

[3] The three first numbers in Newton's scale are black, blue, and white.

NOTE S.--Par. 485.

A chapter on entoptic colours, contained in the supplement to Goethe's works, was translated with the intention of inserting it among the notes, but on the whole it was thought most advisable to omit it. Like many other parts of the "Doctrine of Colours" it might have served as a specimen of what may be achieved by accurate observation unassisted by a mathematical foundation. The whole theory of the polarization of light has, however, been so fully investigated since Goethe's time, that the chapter in question would probably have been found to contain very little to interest scientific readers, for whom it seems chiefly to have been intended. One observation occurs in it which indeed has more reference to the arts; in order to make this intelligible, the leading experiment must be first described, and for this purpose the following extracts may serve.

3.[1]

"The experiment, in its simplest form, is to be made as follows:--let a tolerably thick piece of plate-glass be cut into several squares of an inch and a half; let these be heated to a red heat and then suddenly cooled. The squares of glass which do not split in this operation are now fit to produce the entoptic colours.

4.

"In our mode of exhibiting the phenomenon, the observer is, above all, to betake himself, with his apparatus to the open air. All dark rooms, all small apertures (foramina exigua),[2] are again to be given up. A pure, cloudless sky is the source whence we are derive a satisfactory insight into the appearances.

5.

"The atmosphere being clear, let the observer lay the squares above described on a black surface, so placing them that two sides may be parallel with the plane of vision. When the sun is low, let him hold the squares so as to reflect to the eye that portion of the sky opposite to the sun, and he will then perceive four dark points in the four corners of a light space. If, after this, he turn towards the quarters of the sky at right angles with that where his first observation was made, he will see four bright points on a dark ground: between the two regions the figures appear to fluctuate.

6.

"From this simple reflection we now proceed to another, which, but little more complicated, exhibits the appearance much more distinctly. A solid cube of glass, or in its stead a cube composed of several plates, is placed on a black mirror, or held a little inclined above it, at sun-rise or sun-set. The reflection of the sky being now suffered to fall through the cube on the mirror, the appearance above described will appear more distinctly. The reflection of the sky opposite to the sun presents four dark points on a light ground; the two lateral portions of the sky present the contrary appearance, namely, four light points on a dark ground. The space not occupied by the corner points appears in the first case as a white cross, in the other as a black cross, expressions hereafter employed in describing the phenomena. Before sun-rise or after sun-set, in a very subdued light, the white cross appears on the side of the sun also.[3]

"We thus conclude that the direct reflection of the sun produces a light figure, which we call a white cross; the oblique reflection gives a dark figure, which we call a black cross. If we make the experiment all round the sky, we shall find that a fluctuation takes place in the intermediate regions."

We pass over a variety of observations on the modes of exhibiting this phenomenon, the natural transparent substances which exhibit it best, and the detail of the colours seen within[4] them, and proceed to an instance where the author was enabled to distinguish the "direct" from the "oblique" reflection by means of the entoptic apparatus, in a painter's study.

40.

"An excellent artist, unfortunately too soon taken from us, Ferdinand Jagemann, who, with other qualifications, had a fine eye for light and shade, colour and keeping, had built himself a painting-room for large as well as small works. The single high window was to the north, facing the most open sky, and it was thought that all necessary requisites had been sufficiently attended to.

"But after our friend had worked for some time, it appeared to him, in painting portraits, that the faces he copied were not equally well lighted at all hours of the day, and yet his sitters always occupied the same place, and the serenity of the atmosphere was unaltered.

"The variations of the favourable and unfavourable light had their periods during the day. Early in the morning the light appeared most unpleasantly grey and unsatisfactory; it became better, till at last, about an hour before noon, the objects had acquired a totally different appearance. Everything presented itself to the eye of the artist in its greatest perfection, as he would most wish to transfer it to canvas. In the afternoon this beautiful appearance vanished--the light became worse, even in the brightest day, without any change having taken place in the atmosphere.

"As soon as I heard of this circumstance, I at once connected it in my own mind with the phenomena which I had been so long observing, and hastened to prove, by a physical experiment, what a clear-sighted artist had discovered entirely of himself, to his own surprise and astonishment.

"I had the second[5] entoptic apparatus brought to the spot, and the effect on this was what might be conjectured from the above statement. At mid-day, when the artist saw his model best lighted, the north, direct reflection gave the white cross; in the morning and evening, on the other hand, when the unfavourable oblique light was so unpleasant to him, the cube showed the black cross; in the intermediate hours the state of transition was apparent."

The author proceeds to recall to his memory instances where works of art had struck him by the beauty of their appearance owing to the light coming from the quarter opposite the sun, in "direct reflection," and adds, "Since these decided effects are thus traceable to their cause, the friends of art, in looking at and exhibiting pictures, may enhance the enjoyment to themselves and others by attending to a fortunate reflection."

[1] The numbers, as usual, indicate the corresponding paragraphs in the original.

[2] In the historical part, Goethe has to speak of so many followers of Newton who begin their statements with "Si per foramen exiguum," that the term is a sort of by-word with him.

[3] At mid-day on the 24th of June the author observed the white cross reflected from every part of the horizon. At a certain distance from the sun, corresponding, he supposes, with the extent of halos, the black cross appeared.

[4] Whence the term _entoptic_.

[5] Before described: the author describes several others more or less complicated, and suggests a portable one. "Such plates, which need only be an inch and a quarter square, placed on each other to form a cube, might be set in a brass case, open above and below. At one end of this case a black mirror with a hinge, acting like a cover, might be fastened. We recommend this simple apparatus, with which the principal and original experiment may be readily made. With this we could, in the longest days, better define the circle round the sun where the black cross appears," &c.

NOTE T.--Par. 496.

"Since Goethe wrote, all the earths have been decomposed, and have been shown to be metallic bases united with oxygen; but this does not invalidate his statement."--S. F.

NOTE U.--Par. 502.

The cold nature of black and its affinity to blue are assumed by the author throughout; if the quality is opaque, and consequently greyish, such an affinity is obvious, but in many fine pictures, intense black seems to be considered as the last effect of heat, and in accompanying crimson and orange may be said rather to present a difference of degree than a difference of kind. In looking at the great picture of the globe, we find this last result produced in climates where the sun has greatest power, as we find it the immediate effect of fire. The light parts of black animals are often of a mellow colour; the spots and stripes on skins and shells are generally surrounded by a warm hue, and are brown before they are absolutely black. In combustion, the blackness which announces the complete ignition, is preceded always by the same mellow, orange colour. The representation of this process was probably intended by the Greeks in the black and subdued orange of their vases: indeed, the very colours may have been first produced in the kiln. But without supposing that they were retained merely from this accident, the fact that the combination itself is extremely harmonious, would be sufficient to account for its adoption. Many of the remarks of Aristotle[1] and Theophrastus[2] on the production of black, are derived from the observation of the action of fire, and on one occasion, the former distinctly alludes to the terracotta kiln. That the above opinion as to the nature of black was prevalent in the sixteenth century, may be inferred from Lomazzo, who observes,--"Quanto all' origine e generazione de' colori, la frigidità è la madre della bianchezza: il calore è padre del nero."[3] The positive coldness of black may be said to begin when it approaches grey. When Leonardo da Vinci says that black is most beautiful in shade, he probably means to define its most intense and transparent state, when it is furthest removed from grey.

[1] "De Coloribus."

[2] "De Igne."

[3] "Trattato," &c. p. 191, the rest of the passage, it must be admitted, abounds with absurdities.

NOTE V.--Par. 555.

The nature of vehicles or liquid mediums to combine with the substance of colours, has been frequently discussed by modern writers on art, and may perhaps be said to have received as much attention as it deserves. Reynolds smiles at the notion of our not having materials equal to those of former times, and indeed, although the methods of individuals will always differ, there seems no reason to suppose that any great technical secret has been lost. In these inquiries, however, which relate merely to the mechanical causes of bright and durable colouring, the skill of the painter in the adequate employment of the higher resources of his art is, as if by common consent, left out of the account, and without departing from this mode of considering the question, we would merely repeat a conviction before expressed, viz. that the preservation of internal brightness, a quality compatible with various methods, has had more to do with the splendour and durability of finely coloured pictures than any vehicle. The observations that follow are therefore merely intended to show how far the older written authorities on this subject agree with the results of modern investigation, without at all assuming that the old methods, if known, need be implicitly followed.

On a careful examination of the earlier pictures, it is said that a resinous substance appears to have been mingled with the colours together with the oil; that the fracture of the indurated pigment is shining, and that the surface resists the ordinary solvents.[1] This admixture of resinous solutions or varnishes with the solid is not alluded to, as far as we have seen, by any of the writers on Italian practice, but as the method corresponds with that now prevalent in England, the above hypothesis is not likely to be objected to for the present.

Various local circumstances and relations might seem to warrant the supposition that the Venetian painters used resinous substances. An important branch of commerce between the mountains of Friuli and Venice still consists in the turpentine or fir-resin.[2] Similar substances produced from various trees, and known under the common name of balsams,[3] were imported from the East through Venice, for general use, before the American balsams[4] in some degree superseded them; and a Venetian painter, Marco Boschini, in his description of the Archipelago, does not omit to speak of the abundance of mastic produced in the island of Scio.[5]

The testimonies, direct or indirect, against the employment of any such substances by the Venetian painters, in the solid part of their work, seem, notwithstanding, very conclusive; we begin with the writer just named. In his principal composition, a poem[6] describing the practice and the productions of the Venetian painters, Boschini speaks of certain colours which they shunned, and adds:--"In like manner (they avoided) shining liquids and varnishes, which I should rather call lackers;[7] for the surface of flesh, if natural and unadorned, assuredly does not shine, nature speaks as to this plainly." After alluding to the possible alteration of this natural appearance by means of cosmetics, he continues: "Foreign artists set such great store by these varnishes, that a shining surface seems to them the only desirable quality in art. What trash it is they prize! fir-resin, mastic, and sandarach, and larch-resin (not to say treacle), stuff fit to polish boots.[8] If those great painters of ours had to represent armour, a gold vase, a mirror, or anything of the kind, they made it shine with (simple) colours."[9]

This writer so frequently alludes to the Flemish painters, of whose great reputation he sometimes seems jealous, that the above strong expression of opinion may have been pointed at them. On the other hand it is to be observed that the term _forestieri_, strangers, does not necessarily mean transalpine foreigners, but includes those Italians who were not of the Venetian state.[10] The directions given by Raphael Borghini,[11] and after him by Armenini,[12] respecting the use and preparation of varnishes made from the very materials in question, may thus have been comprehended in the censure, especially as some of these recipes were copied and republished in Venice by Bisagno,[13] in 1642--that is, only six years before Boschini's poem appeared.

Ridolfi's Lives of the Venetian Painters[14] (1648) may be mentioned with the two last. His only observation respecting the vehicle is, that Giovanni Bellini, after introducing himself by an artifice into the painting-room of Antonello da Messina, saw that painter dip his brush from time to time in linseed oil. This story, related about two hundred years after the supposed event, is certainly not to be adduced as very striking evidence in any way.[15]

Among the next writers, in order of time prior to Bisagno, may be mentioned Canepario[16] (1619). His work, "De Atramentis" contains a variety of recipes for different purposes: one chapter, _De atramentis diversicoloribus_, has a more direct reference to painting. His observations under this head are by no means confined to the preparation of transparent colours, but he says little on the subject of varnishes. After describing a mode of preserving white of egg, he says, "Others are accustomed to mix colours in liquid varnish and linseed, or nut-oil; for a liquid and oily varnish binds the (different layers of) colours better together, and thus forms a very fit glazing material."[17] On the subject of oils he observes, that linseed oil was in great request among painters; who, however, were of opinion that nut-oil-excelled it "in giving brilliancy to pictures, in preserving them better, and in rendering the colours more vivid."[18]

Lomazzo (a Milanese) says nothing on the subject of vehicles in his principal work, but in his "Idea del Tempio della Pittura,"[19] he speaks of grinding the colours "in nut-oil, and spike-oil, and other things," the "and" here evidently means _or_, and by "other things" we are perhaps to understand other oils, poppy oil, drying oils, &c.

The directions of Raphael Borghini and Vasari[20] cannot certainly be considered conclusive as to the practice of the Venetians, but they are very clear on the subject of varnish. These writers may be considered the earliest Italian authorities who have entered much into practical methods. In the few observations on the subject of vehicles in Leonardo da Vinci's treatise, "there is nothing," as M. Merimée observes, "to show that he was in the habit of mixing varnish with his colours." Cennini says but little on the subject of oil-painting; Leon Battista Alberti is theoretical rather than practical, and the published extracts of Lorenzo Ghiberti's MS. chiefly relate to sculpture.

Borghini and Vasari agree in recommending nut-oil in preference to linseed-oil; both recommend adding varnish to the colours in painting on walls in oil, "because the work does not then require to be varnished afterwards," but in the ordinary modes of painting on panel or cloth, the varnish is omitted. Borghini expressly says, that oil alone (senza più) is to be employed; he also recommends a very sparing use of it.

The treatise of Armenini (1587) was published at Ravenna, and he himself was of Faenza, so that his authority, again, cannot be considered decisive as to the Venetian practice. After all, he recommends the addition of "common varnish" only for the ground or preparation, as a consolidating medium, for the glazing colours, and for those dark pigments which are slow in drying. Many of his directions are copied from the writers last named; the recipes for varnishes, in particular, are to be found in Borghini. Christoforo Sorte[21] (1580) briefly alludes to the subject in question. After speaking of the methods of distemper, he observes that the same colours may be used in oil, except that instead of mixing them with size, they are mixed on the palette with nut-oil, or (if slow in drying) with boiled linseed-oil: he does not mention varnish. The Italian writers next in order are earlier than Vasari, and may therefore be considered original, but they are all very concise.

The treatise of Michael Angelo Biondo[22] (1549), remarkable for its historical mistakes, is not without interest in other respects. The list of colours he gives is, in all probability, a catalogue of those in general use in Venice at the period he wrote. With regard to the vehicle, he merely mentions oil and size as the mediums for the two distinct methods of oil-painting and distemper, and does not speak of varnish. The passages in the Dialogue of Doni[23] (1549), which relate to the subject in question, are to the same effect. "In colouring in oil," he observes, "the most brilliant colours (that we see in pictures) are prepared by merely mixing them with the end of a knife on the palette." Speaking of the perishable nature of works in oil-painting as compared with sculpture, he says, that the plaster of Paris (gesso) and mastic, with other ingredients of which the ground is prepared, are liable to decay, &c.; and elsewhere, in comparing painting in general with mosaic, that in the former the colours "must of necessity be mixed with various things, such as oils, gums, white or yolk of egg, and juice of figs, all which tend to impair the beauty of the tints." This catalogue of vehicles is derived from all kinds of painting to enforce the argument, and is by no means to be understood as belonging to one and the same method.

An interesting little work,[24] still in the form of a dialogue (Fabio and Lauro), appeared a year earlier; the author, Paolo Pino, was a Venetian painter. In speaking of the practical methods Fabio observes, as usual, that oil-painting is of all modes of imitation the most perfect, but his reasons for this opinion seem to have a reference to the Venetian practice of going over the work repeatedly. Lauro asks whether it is not possible to paint in oil on the dry wall, as Sebastian del Piombo did. Fabio answers, "the work cannot last, for the solidity of the plaster is impenetrable, and the colours, whether in oil or distemper, cannot pass the surface." This might seem to warrant the inference that absorbent grounds were prepared for oil-painting, but there are proofs enough that resins as well as oil were used with the _gesso_ to make the preparation compact. See Doni, Armenini, &c. This writer, again, does not speak of varnish. These appear to be the chief Venetian and Italian authorities[25] of the sixteenth and part of the following century; and although Boschini wrote latest, he appears to have had his information from good sources, and more than once distinctly quotes Palma Giovane.

In all these instances it will be seen that there is no allusion to the immixture of varnishes with the solid colours, except in painting on walls in oil, and that the processes of distemper and oil are always considered as separate arts.[26] On the other hand, the prohibition of Boschini cannot be understood to be universal, for it is quite certain that the Venetians varnished their pictures when done.[27] After Titian had finished his whole-length portrait of Pope Paul III. it was placed in the sun to be varnished.[28] Again, in the archives of the church of S. Niccolo at Treviso a sum is noted (Sept. 21, 1521 ), "per far la vernise da invernisar la Pala dell' altar grando," and the same day a second entry appears of a payment to a painter, "per esser venuto a dar la vernise alla Pala," &c.[29] It is to be observed that in both these cases the pictures were varnished as soon as done;[30] the varnish employed was perhaps the thin compound of naphtha (oglio di sasso) and melted turpentine (oglio d'abezzo), described by Borghini, and after him by Armenini: the last-named writer remarks that he had seen this varnish used by the best painters in Lombardy, and had heard that it was preferred by Correggio. The consequence of this immediate varnishing may have been that the warm resinous liquid, whatever it was, became united with the colours, and thus at a future time the pigment may have acquired a consistency capable of resisting the ordinary solvents. Not only was the surface of the picture required to be warm, but the varnish was applied soon after it was taken from the fire.[31]

Many of the treatises above quoted contain directions for making the colours dry:[32] some of these recipes, and many in addition, are to be found in Palomino, who, however defective as an historian,[33] has left very copious practical details, evidently of ancient date. His drying recipes are numerous, and although sugar of lead does not appear, cardenillo (verdigris), which is perhaps as objectionable, is admitted to be the best of all dryers. It may excite some surprise that the Spanish painters should have bestowed so much attention on this subject in a climate like theirs, but the rapidity of their execution must have often required such an assistance.[34]

One circumstance alluded to by Palomino, in his very minute practical directions, deserves to be mentioned. After saying what colours should be preserved in their saucers under water, and what colours should be merely covered with oiled paper because the water injures them, he proceeds to communicate "a curious mode of preserving oil-colours," and of transporting them from place to place. The important secret is to tie them in bladders, the mode of doing which he enters into with great minuteness, as if the invention was recent. It is true, Christoforo Sorte, in describing his practice in water-colour drawing, says he was in the habit of preserving a certain vegetable green with gum-water in a bladder; but as the method was obviously new to Palomino, there seems sufficient reason to believe that oil-colours, when once ground, had, up to his time, been kept in saucers and preserved under water.[35] Among the items of expense in the Treviso document before alluded to, we find "a pan and saucers for the painters."[36] This is in accordance with Cennini's directions, and the same system appears to have been followed till after 1700.[37]

The Flemish accounts of the early practice of oil-painting are all later than Vasari. Van Mander, in correcting the Italian historian in his dates, still follows his narrative in other respects verbatim. If Vasari's story is to be accepted as true, it might be inferred that the Flemish secret consisted in an oil varnish like copal.[38] Vasari says, that Van Eyck boiled the oils with other ingredients; that the colours, when mixed with this kind of oil, had a very firm consistence; that the surface of the pictures so executed had a lustre, so that they needed no varnish when done; and that the colours were in no danger from water.[39]

Certain colours, as is well known, if mixed with oil alone, may be washed off after a considerable time. Leonardo da Vinci remarks, that verdigris may be thus removed. Carmine, Palomino observes, may be washed off after six years. It is on this account the Italian writers recommend the use of varnish with certain colours, and it appears the Venetians, and perhaps the Italians generally, employed it solely in such cases. But it is somewhat extraordinary that Vasari should teach a mode of painting in oil so different in its results (inasmuch as the work thus required varnish at last) from the Flemish method which he so much extols--a method which he says the Italians long endeavoured to find out in vain. If they knew it, it is evident, assuming his account to be correct, that they did not practice it.

[1] See "Marcucci Saggio Analitico-chimico sopra i colori," &c. Rome, 1816, and "Taylor's Translation of Merimée on Oil-painting," London, 1839. The last-named work contains much useful information.

[2] Italian writers of the 16th century speak of three kinds. Cardanus says, that of the _abies_ was esteemed most, that of the _larix_ next, and that of the _picea_ least. The resin extracted by incision from the last (the pinus abies Linnæi) is known by the name of Burgundy pitch; when extracted by fire it is black. The three varieties occur in Italian treatises on art, under the names of _oglio di abezzo_, _trementina_ and _pece Greca_.

[3] The concrete balsam _benzoe_, called by the Italians _beluzino_, and _belzoino_, is sometimes spoken of as a varnish.

[4] Marcucci supposes that balsam of copaiba was mixed with the pigments by the (later) Venetians.

[5] "L'Archipelago con tutte le Isole," Ven. 1658. The incidental notices of the remains of antiquity in this work would be curious and important if they could be relied on. In describing the island of Samos, for instance, the author asserts that the temple of Juno was in tolerable preservation, and that the statue was still there.

[6] "La Carta del Navegar Pitoresco," Ven. 1660. It is in the Venetian dialect.

[7] Inveriadure (invetriature), literally the glazing applied to earthenware.

[8]

"O de che strazze se fan cavedal!
D'ogio d'avezzo, mastici e sandraca;
E trementina (per no'dir triaca)
Robe, che ilustrerave ogni stival."--p. 338.

The alliteration of the words _trementina_ and _triaca_ is of course lost in a translation.

[9] "I li ha fati straluser co' i colori." Boschini was at least constant in his opinion. In the second edition of his "Ricche Minere della Pittura Veneziana," which appeared fourteen years after the publication of his poem, he repeats that the Venetian painters avoided some colours in flesh "e similmente i lustri e le vernici."

[10] Thus, in the introduction to the "Ricche Minere," Boschini calls the Milanese, Florentine, Lombard, and Bolognese painters, _forestieri_.

[11] "Il Riposo," Firenze, 1584.

[12] "De' Veri Precetti della Pittura," Ravenna, 1587.

[13] "Trattato della Pittura fondato nell' autorità di molti eccellenti in questa professione." Venezia, 1642. Bisagno remarks in his preface, that the books on art were few, and that painters were in the habit of keeping them secret. He acknowledges that he has availed himself of the labours of others, but without mentioning his sources: some passages are copied from Lomazzo. He, however, lays claim to some original observations, and says he had seen much and discoursed with many excellent painters.

[14] "Le Meraviglie dell' Arte," Venezia, 1648.

[15] It has been conjectured by some that this story proved the immixture of varnishes with the colours, and that the oil was only used to dilute them. The epitaph on Antonello da Messina which existed in Vasari's time, alludes to his having mixed the colours with oil.

[16] "Petri Mariæ Caneparii De Atramentis cujuscumque generis," Venet. 1619. It was republished at Rotterdam in 1718.

[17] "Ita quod magis ex hiis evadit atramentum picturæ summopere idoneum." Thus, if _atramentum_ is to be understood, as usual, to mean a glazing colour, the passage can only refer to the immixture of varnish with the transparent colours applied last in order.

[18] In a passage that follows respecting the mode of extracting nut-oil, Caneparius appears to mistranslate Galen, c. 7--"De Simplicium Medicamentorum facultatibus." The observations of Galen on this subject, and on the drying property of linseed, may have given the first hint to the inventors of oil-painting. The custom of dating the origin of this art from Van Eyck is like that of dating the commencement of modern painting from Cimabue. The improver is often assumed to be the inventor.

[19] Milan, 1590.

[20] The particulars here alluded to are to be found in the first edition of Vasari (1550) as well as the second.--v. i. c. 21, &c.

[21] "Osservasioni nella Pittura." In Venezia, 1580. Sorte, who, it appears, was a native of Verona, had worked in his youth with Giulio Romano, at Mantua, and communicates the methods taught him by that painter, for giving the true effects of perspective in compositions of figures. He is, perhaps, the earliest who describes the process of water-colour painting as distinguished from distemper and as adapted to landscape, if the art he describes deserves the name.

[22] "Della nobilissima Pittura e sua Arte," Venezia, 1549. Biondo is so ignorant as to attribute the Last Supper, by Leonardo da Vinci, to Mantegna.

[23] "Disegno del Doni," in Venezia, 1549.

[24] "Dialogo di Pittura," Venezia, 1548. Pino, in enumerating the celebrated contemporary artists, does not include Paul Veronese, for a very obvious reason, that painter being at the time only about 17 years of age. Sorte, who wrote thirty years later, mentions "l'eccellente Messer Paulino nostro," alone.