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 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.