t is absolutely necessary is, that there be no confusion or
distraction, no conflicting masses--in fact, that the picture tell its
tale at once and effectually. A very good plate is given by Mr Burnet of
the "Marriage of Cana," by Paul Veronese. Sir Joshua avoids entering
upon rules that belong to "the detail of the art." He meets with
combatants, as might have been expected, where he is thus particular. We
will extract the passage which has been controverted, and to oppose the
doctrine of which, Gainsborough painted his celebrated "Blue Boy."

"Though it is not my _business_ to enter into the detail of our art, yet
I must take this opportunity of mentioning one of the means of producing
that great effect which we observe in the works of the Venetian
painters, as I think it is not generally known or observed, that the
masses of light in a picture be always of a warm mellow colour, yellow
red or yellowish white; and that the blue, the grey, or the green
colours be kept almost entirely out of these masses, and be used only to
support and set off these warm colours; and for this purpose a small
proportion of cold colours will be sufficient. Let this conduct be
reversed; let the light be cold, and the surrounding colours warm, as we
often see in the works of the Roman and Florentine painters, and it will
be out of the power of art, even in the hands of Rubens or Titian, to
make a picture splendid and harmonious." Le Brun and Carlo Maratti are
censured as being "deficient in this management of colours." The
"Bacchus and Ariadne," now in our National Gallery, has ever been
celebrated for its harmony of colour. Sir Joshua supports his theory or
rule by the example of this picture: the red of Ariadne's scarf, which,
according to critics, was purposely given to relieve the figure from the
sea, has a better object. "The figure of Ariadne is separated from the
great group, and is dressed in blue, which, added to the colour of the
sea, makes that quantity of cold colour which Titian thought necessary
for the support and brilliancy of the great group; which group is
composed, with very little exception, entirely of mellow colours. But as
the picture in this case would be divided into two distinct parts, one
half cold and the other warm, it was necessary to carry some of the
mellow colours of the great group into the cold part of the picture, and
a part of the cold into the great group; accordingly Titian gave Ariadne
a red scarf, and