of transpositions leads us inevitably into consideration of the great
secret of Corot's art, his employment of what is known in studios as
values.

By values is meant the amount of light and shadow contained in a tone.
The relation of a half-tint to the highest light, which is represented
by the white paper, the relation of a shadow to the deepest black,
which is represented by the chalk pencil, is easy enough to perceive
in a drawing; but when the work is in colour the values, although not
less real, are more difficult to estimate. For a colour can be
considered from two points of view: either as so much colouring
matter, or as so much light and shade. Violet, for instance, contains
not only red and blue in proportions which may be indefinitely varied,
but also certain proportions of light and shade; the former tending
towards the highest light, represented on the palette by flake white;
the latter tending towards the deepest dark, represented on the
palette by ivory black.

Similar to a note in music, no colour can be said to be in itself
either false or true, ugly or beautiful. A note and a colour acquire
beauty and ugliness according to their associations; therefore to
colour well depends, in the first instance, on the painter's knowledge
and intimate sense of the laws of contrast and similitude. But there
is still another factor in the art of colouring well; for, just as the
musician obtains richness and novelty of expression by means of a
distribution of sound through the instruments of the orchestra, so
does the painter obtain depth and richness through a judicious
distribution of values. If we were to disturb the distribution of
values in the pictures of Titian, Rubens, Veronese, their colour would
at once seem crude, superficial, without cohesion or rarity. But some