Note, if the light should come in at the door-way, instead of the window, the gradation then would be reversed, but still the effect of recession would be just the same, as this shade ever complies with the perspective lines.

In the next place, let us observe the ovolo, or quarter-round in a cornice, fronting the eye in like manner, by which may be seen an example of the second species; where, on its most projecting part, a line of light is seen, from whence these shades retire contrary ways, by which the curvature is understood.

And, perhaps, in the very same cornice may be seen an example of the third species, in that ornamental member called by the architects cyma recta, or P. 103 talon, which indeed is no more than a larger sort of waving or ogee moulding; wherein, by the convex parts gently gliding into the concave, you may see four contrasted gradating shades, shewing so many varied recessions from the eye; by which we are made as sensible of its waving form as if we saw the profile out-line of some corner of it, where it is mitred, as the joiners term it. Note, when these objects have a little gloss on them these appearances are most distinct.

Lastly, the serpentine shade may be seen (light and situation as before) by the help of the following

Note also, that when planes are seen parallel to the eye in open day-light, they have scarce any round gradating or penciling shade at all, but appear merely as uniform prime tints, because the rays of light are equally diffused upon them. Nevertheless, give them but obliquity, they will more or less exhibit the retiring shade.

figure, as thus ; imagine the horn, figure 57, plate 2, to be of so soft a nature, that with the fingers only, it might be pressed into any shape; then beginning gently from the middle of the dotted line, but pressing harder and harder all the way up the lesser end, by such pressure there would be as much concave above, as would remain convex below, which would bring it equal in variety or beauty to the ogee moulding; but after this, by giving the whole a twist, like figure 58, these shades must unavoidably change their appearances, and in some measure, twist about as the concave and convex parts are twisted, and consequently thereby P. 104 add that variety, which of course will give this species of shade, as much the preference to the foregoing, as forms composed of serpentine lines have, to those composed only of the waving. See chap. 9. and chap. 10,

I should not have given my reader the trouble of completing, by the help of his imagination, the foregoing figure, but as it may contribute to the more ready and particular conception of that intricate variety, which twisted figures give to this species of shade, and to facilitate his understanding the cause of its beauty, wherever it may be seen on surfaces of ornament, when it will be found no where more conspicuous than in a fine face, as will be seen upon further enquiry.

The dotted line*, which begins from the concave part, under the arch of the brow, near the nosé, and from thence winding down by the corner of the eye, and there turning obliquely with the round of the

*Fig. 97. B. p. 1.

cheek, shews the course of that twist of shades in a face, which was before described by the horn; and which may be most perfectly seen in the life, or in a marble busto, together with the following additional circumstances still remaining to be described.

As a face is for the most part round, it is therefore apt to receive reflected light on its shadowy side', which not only adds more beauty by another pleasing P. 105 tender gradation, but also serves to distinguish the roundness of the cheeks, &c. from such parts as sink and fall in because concavities do not admit of reflections, as convex forms do 2.

I have now only to add, that as before observed, chap. 4, page 23, that the oval hath a nobles implicity in it, more equal to its variety than any other object in nature; and of which the general form of a face is composed; therefore, from what has been now shewn, the general gradation-shade belonging to it, must consequently be adequate thereto, and which evidently gives a delicate softness to the whole composition of a face; insomuch that every little dent, crack, or scratch, the form receives, its shadows also suffer with

1 Note, though I have advised the observing objects by a front light, for the sake of the better distinguishing our four fundamental species of shades, yet objects in general are more advantageously and agreeably seen by light coming side-ways upon them, and therefore generally chose in paintings; as it gives an additional reflected softness, not unlike the gentle tone of an echo in music.

2 As an instance that convex and concave would appear the same, if the former were to have no reflection thrown upon, observe the ovolo and cavetto, or channel, in a cornice, placed near together, and seen by a front light, when they will each of them, by turns, appear either concave, or convex, as fancy shall direct.

P. 106

it, and help to shew the blemish. Even the least
roughness interrupts and damages that soft gradating
play of shades which fall upon it. Mr. Dryden, de-
scribing the light and shades of a face, in his epistle
to Sir Godfrey Kneller the portrait painter, seems, by
the penetration of his incomparable genius, to have
understood that language in the works of nature,
which the latter, by means of an exact eye and a
strict obeying hand, could only faithfully transcribe;
when he says,

Where light to shades descending, plays, not strives,
Dies by degrees, and by degrees revives.

CHAPTER XIII.

OF COMPOSITION

WITH REGARD TO LIGHT, SHADE, AND COLOURS.

UNDER this head I shall attempt shewing what it is that gives the appearance of that hollow or vacant space in which all things move so freely; and in what manner light, shade and colours, mark or point out the distances of one object from another, and occasion an agreeable play upon the eye, called by the painters a fine keeping, and pleasing composition of light and shade. Herein my design is to consider this matter as a performance of nature without, or before the eye; I mean, as if the objects with their shades, &c. were in fact circumstanced as they appear, and as the unskilled in optics take them to be. And let it be remarked throughout this chapter, that the pleasure arising from composition, as in a fine landskip, &c. is chiefly owing to the dispositions and assemblages of light and shades, which are so ordered by the principles called OPPOSITION, BREADTH, and SIMPLICITY, as to produce a just and distinct perception of the objects before us.

Experience teaches us that the eye may be subdued and forced into forming and disposing of objects even quite contrary to what it would naturally see