If Poussin, in imitation of the ancients, represents Apollo driving his chariot out of the sea by way of representing the sun rising, if he personifies lakes and rivers, it is no ways offensive in him; but seems perfectly of a piece with the general air of the picture.  On the contrary, if the figures which people his pictures had a modern air or countenance, if they appeared like our countrymen, if the draperies were like cloth or silk of our manufacture, if the landscape had the appearance of a modern view, how ridiculous would Apollo appear instead of the sun, an old man or a nymph with an urn instead of a river or lake.

I cannot avoid mentioning here a circumstance in portrait painting which may help to confirm what has been said.

When a portrait is painted in the historical style, as it is neither an exact minute representation of an individual nor completely ideal, every circumstance ought to correspond to this mixture.  The simplicity of the antique air and attitude, however much to be admired, is ridiculous when joined to a figure in a modern dress.  It is not to my purpose to enter into the question at present, whether this mixed style ought to be adopted or not; yet if it is chosen it is necessary it should be complete and all of a piece:  the difference of stuffs, for instance, which make the clothing, should be distinguished in the same degree as the head deviates from a general idea.

Without this union, which I have so often recommended, a work can have no marked and determined character, which is the peculiar and constant evidence of genius.  But when this is accomplished to a high degree, it becomes in some sort a rival to that style which we have fixed as the highest.

Thus I have given a sketch of the characters of Rubens and Salvator Rosa, as they appear to me to have the greatest uniformity of mind throughout their whole work.  But we may add to these, all these artists who are at the head of the class, and have had a school of imitators from Michael Angelo down to Watteau.  Upon the whole it appears that setting aside the ornamental style, there are two different paths, either of which a student may take without degrading the dignity of his art.  The first is to combine the higher excellences and embellish them to the greatest advantage.  The other is to carry one of these excellences to the highest degree.  But those who possess neither must be classed with them, who, as Shakespeare says, are men of no mark or likelihood.

I inculcate as frequently as I can your forming yourselves upon great principles and great models.  Your time will be much misspent in every other pursuit.  Small excellences should be viewed, not studied; they ought to be viewed, because nothing ought to escape a painter’s observation, but for no other reason.