Frontispiece. It will be observed that in the complete painting the central figure apparently wears a startled expression, but that this is entirely due to the surroundings and action, is shown by the substitution of the face of the central figure for that of the Virgin in the Sistine Madonna, Plate 8. (See Page 139.)

  Plate 12.—Portrait Heads of the Greek Type, Fourth Century, b.c. (See Page 145) 130 (a). Head of Plato. (Copenhagen Museum.) (b). Term of Euripides. (Naples Museum.)   Plate 13.—Portrait Heads of the Time of Imperial Rome. (See Page 145) 146 (a). Vespasian. (Naples Museum.) (b). Hadrian. (Athens Museum.)   Plate 14.—Sacrifice of Iphigenia, from a Pompeian Fresco. (Roux Ainé's Herculanum et Pompei, Vol. III) 160 This work is presumed to be a copy of the celebrated picture of Timanthes, in which the head of Agamemnon was hidden because the artist could see no other way of expressing extreme grief without distorting the features. (See Pages 168 and 339.)   Plate 15.—All's Well, by Winslow Homer. (Boston Museum, U. S. A.) 176 An instance where the permanent beauty of a picture is killed by an open mouth. After a few moments' inspection, it will be observed that the mouth appears to be kept open by a wedge. (See Page 176.)   Plate 16.—Hercules Contemplating Death, by A. Pollaiuolo. (Frick Collection, New York.) 190 The only known design of this nature which appears to exist in any of the arts. (See Pages 190 and 343.)   Plate 17.—Arcadian Landscape, by Claude Lorraine. (National Gallery, London) 198 A fine illusion of opening distance created by the precise rendering of the aerial perspective. The illusion is of course unobservable in the reproduction owing to its small size and the want of colour. (See Page 198).   Plate 18.—Landscape, by Hobbema. (Met. Museum, New York) 210 A fine example of Hobbema's work. A strong light is thrown in from the back to enable the artist to multiply his signs for the purpose of deepening the apparent distance. (See Page 202.)   Plate 19.—Landscape, by Jacob Ruysdael, (National Gallery, London) 220 Example of an illusion of movement in flowing water. (See Page 204.)   Plate 20.—The Storm, by Jacob Ruysdael. (Berlin Gallery) 232 Exhibiting an excellent illusion of motion, due to the faithful representation of a series of consecutive movements of water as the vessel passes through it. The illusion is practically lost in the reproduction, but the details of design may be observed. (See Page 206.)   Plate 21.—The Litta Madonna, by Lionardo da Vinci. (Hermitage) 240 This is perhaps the best example known of an illusion of relief secured by shading alone. (See Page 240.)   Plate 22.—Christ on the Cross, by Van Dyck. (Antwerp Museum) public@vhost@g@gutenberg@html@files@36427@[email protected]#Page_252"