Ideal, true naturalist, character of, iii. 77-91; high, necessity of reality in, iii. 80, 81, 91; its operation on historical art, iii. 89-91; in landscape produces the heroic, v. [206].

Ideal, true purist, iii. 71-76.

Ideal, false, various forms of, iii. 69, iv. 308, 310 (plates); results of pursuit of the, iii. 61, 63; religious, iii. 44, 60; well-executed, dulls perception of truth, iii. 48-52; profane, iii. 61-69; of the modern drama, iv. 321.

Ideal, superhuman, ii. 212, 224; expression of, by utmost degree of human beauty, ii. 214.

Ideality, not confined to one age or condition, ii. 109-117; expressible in art, by abstraction of form, color, or texture, ii. 201.

Illumination, distinguished from painting by absence of shadow, iii. 99; pigments used in, iii. 223; decline of the art of, to what traceable, iv. 359; of MSS. in thirteenth century, illustrating treatment of natural form, iii. 207, 208, iv. 76; of MSS. in fifteenth century, illustrating treatment of landscape art, iii. 201; of MSS. in sixteenth century, illustrating idea of rocks, iii. 239; of missals, illustrating later ideas of rocks and precipices, iv. 253; of missal in British Museum, illustrating German love of horror, iv. 328; of MSS. in fifteenth century, German coarseness contrasted with grace and tenderness of thirteenth century, iv. 335; representation of sun in, iii. 318.

Imagination, threefold operation of, ii. 146; why so called, iii. 132; defined, ii. 151; functions of, ii. 10, 143, 188, iii. 45, iv. 31; how strengthened by feeding on truth and external nature, i. 427, ii. 191; tests of presence of, ii. 155, 169, 207; implies self-forgetfulness, i. 306; importance of in art, iii. 38; Dugald Stewart’s definition of, ii. 143, 145; conscious of no rules, ii. 155; makes use of accurate knowledge, ii. 109, iii. 40; noble only when truthful, ii. 161, iii. 123, iv. 30; entirety of its grasp, ii. 156, 179, v. [187], [190]; its delight in the character of repose, ii. 66; verity of, ii. 161, 188, 211, iii. 30, 107, 133; power of, ii. 158, 206, iii. 10, 11, 131, 287, iv. 19, 30; calmness essential to, v. [191]; always the seeing and asserting faculty, iii. 211; charm of expectant, iv. 131; pleasure derived from, how enhanced, iii. 281; highest form of, ii. 146; always right when left to itself, iii. 106; how excited by mountain scenery, iv. 23, 222, v. [216], [235]; influence of clouds on, v. [141]; searching apprehension of, ii. 164, 165, 169, 183, 188, 195, iii. 107; distinguished from fancy, ii. 166-170, 194, 201; signs of, in language, ii. 165; how shown in sculpture, ii. 184-187; work of, distinguished from composition, ii. 154-158; what necessary to formation of, v. [189]-191.

Imagination, penetrative, ii. 163-191; associative, ii. 147-162; contemplative, ii. 192-211.

Imitation, power of deceiving the senses, i. 17; why reprehensible, i. 18, 19, 21, 34, 73, 416, iv. 136; no picture good which deceives by, i. 25; when right, in architectural ornament, ii. 205; of flowers, v. [92]; was least valued in the thirteenth century, iii. 18, 199, 209; general pleasure in deceptive effects of, iii. 16; when made an end of art, i. 74, 143; began, as a feature of art, about 1300, iii. 203; of what impossible, i. 77, 157, 164, 371, 372, ii. 203, iii. 20, 129, v. [91]; definition of ideas of, i. 13, 20.

Infinity, typical of redeemed life, iv. 80; expressed in nature by curvature and gradation, ii. 45-48; of gradation, i. 210, 224, ii. 47; of variety in nature’s coloring, i. 168, 172, 325, iv. 127; of nature’s fulness, i. 195, v. [99]; of clouds, i. 218, 235, v. [110], [113]; of detail in mountains, i. 290, 297; of curvature, i. 315, ii. 60, iv. 262-269, v. [39]; expressed by distance, ii. 41; not implied by vastness, ii. 49; the cause of mystery, iv. 58; of mountain vegetation, iv. 288; absence of, in Dutch work, v. [37]; general delight in, ii. 42-44.