entirely by adaptations of the Roman shaft and arch, the lower story being formed by a thick mass of wall lightened by ordinary semicircular round-headed niches, like those used so extensively afterwards in renaissance architecture, each niche flanked by a pair of shafts standing clear of the wall, and bearing deeply moulded arches thrown over the niche. The wall with its pillars thus forms a series of massy buttresses (as seen in the ground plan), on the top of which is an open gallery, backed by a thinner wall, and roofed by arches whose shafts are set above the pairs of shafts below. On the heads of these arches rests the roof. We have, therefore, externally a heptagonal apse, chiefly of rough and common brick, only with marble shafts and a few marble ornaments; but for that very reason all the more interesting, because it shows us what may be done, and what was done, with materials such as are now at our own command; and because in its proportions, and in the use of the few ornaments it possesses, it displays a delicacy of feeling rendered doubly notable by the roughness of the work in which laws so subtle are observed, and with which so thoughtful ornamentation is associated.
§ XV. First, for its proportions: I shall have occasion in Chapter V. to dwell at some length on the peculiar subtlety of the early Venetian perception for ratios of magnitude; the relations of the sides of this heptagonal apse supply one of the first and most curious instances of it. The proportions above given of the nave and aisles might have been dictated by a mere love of mathematical precision; but those of the apse could only have resulted from a true love of harmony.
In fig. 6, Plate I. the plan of this part of the church is given on a large scale, showing that its seven external sides are arranged on a line less than a semicircle, so that if the figure were completed, it would have sixteen sides; and it will be observed also, that the seven sides are arranged in four magnitudes, the widest being the central one. The brickwork is so much worn away, that the measures of the arches are not easily ascertainable, but those of the plinth on which they stand, which is nearly uninjured, may be obtained accurately. This plinth is indicated by the open line in the ground plan, and its sides measure respectively:
§ XVI. Now observe what subtle feeling is indicated by this delicacy of proportion. How fine must the perceptions of grace have been in those builders who could not be content without some change between the second and third, the fifth and sixth terms of proportion, such as should oppose the general direction of its cadence, and yet were content with a diminution of two inches on a breadth of seven feet and a half! For I do not suppose that the reader will think the curious lessening of the third and fifth arch a matter of accident, and even if he did so, I shall be able to prove to him hereafter that it was not, but that the early builders were always desirous of obtaining some alternate proportion of this kind. The relations of the numbers are not easily comprehended in the form of feet and inches, but if we reduce the first four of them into inches, and then subtract some constant number, suppose 75, from them all, the remainders 4, 16, 14, 19, will exhibit the ratio of proportion in a clearer, though exaggerated form.
§ XVII. The pairs of circular spots at b, c, d, etc., on the ground plan fig. 6, represent the bearing shafts, which are all of solid marble as well as their capitals. Their measures and various other particulars respecting them are given in Appendix 6. “Apse of Murano;” here I only wish the reader to note the coloring of their capitals. Those of the two single shafts in the angles (a, h) are both of deep purple marble; the two next pairs, b and g, are of white marble; the pairs c and f are of purple, and d and e are of white: thus alternating with each other on each side; two white meeting in the centre. Now observe, the purple capitals are all left plain; the white are all sculptured. For the old builders knew that by carving the purple capitals they would have injured them in two ways: first, they would have mixed a certain quantity of grey shadow with the surface hue, and so adulterated the purity of the color; secondly, they would have drawn away the thoughts from the color, and prevented the mind from fixing upon it or enjoying it, by the degree of attention which the sculpture would have required. So they left their purple capitals full broad masses of color; and sculptured the white ones, which would otherwise have been devoid of interest.
§ XVIII. But the feature which is most to be noted in this apse is a band of ornament, which runs round it like a silver girdle, composed of sharp wedges of marble, preciously inlaid, and set like jewels into the brickwork; above it there is another band of triangular recesses in the bricks, of nearly similar shape, and it seems equally strange that all the marbles should have fallen from it, or that it should have been originally destitute of them. The reader may choose his hypothesis; but there is quite enough left to interest us in the lower band, which is fortunately left in its original state, as is sufficiently proved by the curious niceties in the arrangement of its colors, which are assuredly to be attributed to the care of the first builder. A word or two, in the first place, respecting the means of color at his disposal.
§ XIX. I stated that the building was, for the most part, composed of yellow brick. This yellow is very nearly pure, much more positive and somewhat darker than that of our English light brick, and the material of the brick is very good and hard, looking, in places, almost vitrified, and so compact as to resemble stone. Together with this brick occurs another of a deep full red, and more porous substance, which is used for decoration chiefly, while all the parts requiring strength are composed of the yellow brick. Both these materials are cast into any shape and size the builder required, either into curved pieces for the arches, or flat tiles for filling the triangles; and, what is still more curious, the thickness of the yellow bricks used for the walls varies considerably, from two inches to four; and their length also, some of the larger pieces used in important positions being a foot and a half long.
With these two kinds of brick, the builder employed five or six kinds of marble: pure white, and white veined with purple; a brecciated marble of white and black; a brecciated marble of white and deep green; another, deep red, or nearly of the color of Egyptian porphyry; and a grey and black marble, in fine layers.
§ XX. The method of employing these materials will be understood at once by a reference to the opposite plate (Plate III.), which represents two portions of the lower band. I could not succeed in expressing the variation and chequering of color in marble, by real tints in the print; and have been content, therefore, to give them in line engraving. The different triangles are, altogether, of ten kinds:
a. Pure white marble with sculptured surface (as the third and fifth in the upper series of Plate III.).
b. Cast triangle of red brick with a sculptured round-headed piece of white marble inlaid (as the first and seventh of the upper series, Plate III.).
c. A plain triangle of greenish black marble, now perhaps considerably paler in color than when first employed (as the second and sixth of the upper series of Plate III.).
d. Cast red brick triangle, with a diamond inlaid of the above-mentioned black marble (as the fourth in the upper series of Plate III.).
e. Cast white brick, with an inlaid round-headed piece of marble, variegated with black and yellow, or white and violet (not seen in the plate).
f. Occurs only once, a green-veined marble, forming the upper part of the triangle, with a white piece below.
g. Occurs only once. A brecciated marble of intense black and pure white, the centre of the lower range in Plate III.
h. Sculptured white marble with a triangle of veined purple marble inserted (as the first, third, fifth, and seventh of the lower range in Plate III.).
i. Yellow or white marble veined with purple (as the second and sixth of the lower range in Plate III.).
k. Pure purple marble, not seen in this plate.
III.