Medium Employed.—He painted the picture on the wall in tempera, not, according to the legend which sprung up within twenty years of its completion, in oil. The tempera vehicle, per haps including new experimental ingredients, did not long hold firmly to its plaster ground, nor that to the wall. Flaking and scaling set in ; hard crusts of mildew formed, dissolved and re formed with changes of weather over both the loosened parts and those that remained firm. Decade after decade these proc esses went on, a rain of minute scales and grains falling, accord ing to one witness, continually from the surface, till the picture seemed to be perishing altogether. In the 18th century attempts were first made at restoration. They all proceeded on the false assumption, dating from the early years of the 16th century, that the work had been executed in oil. With oil it was accordingly at one time saturated in hopes of reviving the colours. Other ex perimenters tried various "secrets," which for the most part meant deleterious glues and varnishes. Fortunately not very much of actual repainting was accomplished except on some parts of the garments. The chief operations were carried on by Bellotti in 1726, by Mazza in 177o, and by Barezzi in 1819 and the follow ing years. None of them arrested, some actually accelerated, the natural agencies of decay.
Yet this mere ghost of a picture, this evocation, half vanished as it was, by a great world-genius of a mighty spiritual world event, remained a thing indescribably impressive. The ghost has now been brought back to much of true life again by the skill of the most scrupulous of all restorers, Cavaliere Cavenaghi, who, found it possible to secure to the wall the innumerable blistered flakes and scales of the original work that yet remained, to clear the surface thus obtained of much of the obliterating accretions and to bring the whole to unity by touching tenderly in with tempera the spots and spaces actually left bare. A further gain obtained through these operations has been the uncovering, im mediately above the main subject, of a beautiful scheme of painted lunettes and vaultings, the lunettes filled by Leonardo's hand with inscribed scutcheons and interlaced plait or knot orna ments (intrecciarnenti), the vaultings with stars on a blue ground.
Composition.—Leonardo's "Last Supper," for all its injuries, became from the first for all Christendom the typical representa tion of the scene. Goethe in his famous criticism has said all that needs to be said of it. The painter has departed from prece dent in grouping the disciples, with their Master in the midst, along the far side and the two ends of a long, narrow table, and in leaving the near or service side of the table towards the spec tator free. The chamber is seen in a perfectly symmetrical per spective, its rear wall pierced by three plain openings which admit the sense of quiet distance and mystery from the open landscape beyond ; by the central of these openings, which is the widest of the three, the head and shoulders of the Saviour are framed in.
On His right and left are ranged the disciples in equal numbers. The furniture and accessories of the chamber, very simply con ceived, have been rendered with scrupulous exactness and dis tinctness; yet they leave to the human and dramatic elements the absolute mastery of the scene. The serenity of the holy company has within a moment been broken by the words of their Master, "One of you shall betray Me." In the agitation of their con sciences and affections, the disciples have started into groups or clusters along the table, some standing, some still remaining seated. There are four of these groups, of three disciples each, and each group is harmoniously interlinked by some natural con necting action with the next. Leonardo, though no special student of the Greeks, has perfectly carried out the Greek principle of expressive variety in particulars subordinated to general sym metry. He has used all his acquired science of linear and aerial perspective to create an almost complete illusion to the eye, but an illusion that has in it nothing trivial, and in heightening our sense of the material reality of the scene only heightens its pro found spiritual impressiveness and gravity. The results of his intensest meditations on the psychology and the human and divine significance of the event (on which he has left some pregnant hints in written words of his own) are perfectly fused with those of his subtlest technical calculations on the rhythmical balanc ing of groups and arrangement of figures in space.
Preparatory Sketches.—Of authentic preparatory studies for this work there remain but few. There is a sheet at the Louvre of much earlier date than the first idea or commission for this particular picture, containing some nude sketches for the arrange ment of the subject; another later and farther advanced, but still probably anterior to the practical commission, at Venice, and a ms. sheet of great interest at the Victoria and Albert museum, on which the painter has noted in writing the dramatic motives appropriate to the several disciples. At Windsor and Milan are a few finished studies in red chalk for the heads. A highly-reputed series of life-sized chalk drawings of the same heads, of which the greater portion is at Weimar, consists of early copies, and is interesting though having no just claim to origi nality. Scarcely less doubtful is the celebrated unfinished and injured study of the head of Christ at the Brera, Milan.