book on light and shade.—­On the shape of cast shadows (188—­191).—­On the outlines of cast shadows (192—­195).—­On the relative size of cast shadows (196. 197).—­Effects on cast shadows by the tone of the back ground (198).—­A disputed proposition (199).—­On the relative depth of cast shadows (200—­202).—­Fifth book on light and shade.—­Principles of reflection (203. 204).—­On reverberation (205).—­Reflection on water (206. 207).—­Experiments with the mirror (208—­210).—­Appendix:—­On shadows in movement (211—­212).—­Sixth book on light and shade.—­The effect of rays passing through holes (213. 214).—­On gradation of shadows (215. 216).—­On relative proportion of light and shadows (216—­221).

IV.

PERSPECTIVE OF DISAPPEARANCE

Definition (222. 223).—­An illustration by experiment (224).—­A guiding rule (225).—–­An experiment (226).—­On indistinctness at short distances (227—­231).—­On indistinctness at great distances (232—­234).—­The importance of light and shade in the Prospettiva de’ perdimenti (235—­239).—­The effect of light or dark backgrounds on the apparent size of objects (240—­250).—­Propositions on Prospettiva de’ perdimenti from Ms. C. (250—­262).

V.

THEORY OF COLOURS

The reciprocal effects of colours on objects placed opposite each other (263—­271).—­Combination of different colours in cast shadows (272).—­The effect of colours in the camera obscura (273. 274).—­On the colours of derived shadows (275. 276).—­On the nature of colours (277. 278).—­On gradations in the depth of colours (279. 280).—­On the reflection of colours (281—­283).—­On the use of dark and light colours in painting (284—­286).—­On the colours of the rainbow (287—­288).

VI.

PERSPECTIVE OF COLOUR AND AERIAL PERSPECTIVE

General rules (289—­291).—­An exceptional case (292).—­An experiment (293).—­The practice of the Prospettiva de’ colori (294).—­The rules of aerial perspective (295—­297).—­On the relative density of the atmosphere (298—­299).—­On the colour of the atmosphere (300—­307).

VII.

ON THE PROPORTIONS AND ON THE MOVEMENTS OF THE HUMAN FIGURE

Preliminary observations (308. 309).—­Proportions of the head and face (310—­318).—­Proportions of the head seen in front (319—­321).—­Proportions of the foot (322—­323).—­Relative proportions of the hand and foot (324).—­Relative proportions of the foot and of the face (325—­327).—­Proportions of the leg (328—­331).—­On the central point of the whole body (332).—­The relative proportions of the torso and of the whole figure (333).—­The relative proportions