LINEAR PERSPECTIVE

General remarks on perspective (40—­41).—­The elements of perspective:—­of the point (42—­46).—­Of the line (47—­48).—­The nature of the outline (49).—­Definition of perspective (50).—­The perception of the object depends on the direction of the eye (51).—­Experimental proof of the existence of the pyramid of sight (52—­55).—­The relations of the distance point to the vanishing point (55—­56).—­How to measure the pyramid of vision (57).—­The production of the pyramid of vision (58—­64).—­Proof by experiment (65—­66).—­General conclusions (67).—­That the contrary is impossible (68).—­A parallel case (69).—­The function of the eye, as explained by the camera obscura (70—­71).—­The practice of perspective (72—­73).—­Refraction of the rays falling upon the eye (74—­75).—­The inversion of the images (76).—­The intersection of the rays (77—­82).—­Demonstration of perspective by means of a vertical glass plane (83—­85.)—­The angle of sight varies with the distance (86—­88).—­Opposite pyramids in juxtaposition (89).—­On simple and complex perspective (90).—­The proper distance of objects from the eye (91—­92).—­The relative size of objects with regard to their distance from the eye (93—­98).—­The apparent size of objects denned by calculation (99—­106).—­On natural perspective (107—­109).

III.

SIX BOOKS ON LIGHT AND SHADE

General introduction.—­Prolegomena (110).—­Scheme of the books on light and shade (111).—­Different principles and plans of treatment (112—­116).—­Different sorts of light (117—­118).—­Definition of the nature of shadows (119—­122).—­Of the various kinds of shadows (123—­125).—­Of the various kinds of light (126—­127).—­General remarks (128—­129).—­First book on light and shade.—­On the nature of light (130—­131).—­The difference between light and lustre (132—­135).—­The relations of luminous to illuminated bodies (136).  —­Experiments on the relation of light and shadow within a room (137—­140).—­Light and shadow with regard to the position of the eye (141—­145).—­The law of the incidence of light (146—­147).—­Second book on light and shade.—­Gradations of strength in the shadows (148—­149).—­On the intensity of shadows as dependent on the distance from the light (150—­152).—­On the proportion of light and shadow (153—­157).—­Third book on light and shade.—­Definition of derived shadow (158—­159).—­Different sorts of derived shadows (160—­162).—­On the relation of derived and primary shadow (163—­165).—­On the shape of derived shadows (166—­174).—­On the relative intensity of derived shadows (175—­179).—­Shadow as produced by two lights of different size (180—­181).—­The effect of light at different distances (182).—­Further complications in the derived shadows (183—­187).—­Fourth