tirely spoilt through carelessness in drawing reflex¬
 ions, and some of the more common errors are pointed
 out in the first two chapters. These are easily cor¬
 rected, but when we come to the question of colour
 the problem is more complicated. There are so many
 factors to take into account, and these factors are so
 variously combined in different cases, that it is diff¬
 cult, and often impossible, to lay down definite direc¬
 tions. [his is particularly the case in rough or rippled
 water, the colours of which are considered in Chapter
 IV, but even here an acquaintance with the ele¬
 mentary principles will be of use. It will enable the
 student when at work to test the correctness of his
 own drawings, and in his common observations will
 constantly quicken his perception of subtle differ¬
 ences of colour and tone which might easily have
 escaped him. To give an illustration. [here are
 probably few people who either think that all colour
 seen in water belongs to the water or suppose it to
 be entirely due to reflexion, for no one who has at¬
 tempted to paint the sea, or taken the trouble to con¬
 sider the matter, can have failed to realize that, though
 the water shows colour of its own, it is largely affected
 by the colour of the sky. But many amateurs possess
 only an imperfect knowledge of the question, with
 the result that in marine paintings we frequently
 notice a lack of adequate harmony in colour between
 sea and sky, and perhaps as often an exaggerated ex¬
 pression of it. It is hoped that such persons will be
 enabled to appreciate more accurately the extent and
 the limits of this harmony by a consideration of the
 conditions on which they depend.