s of intervening air between any
given hue of the nearest, and most distant, objects; but let us assume
it, in courtesy to the masters of aerial perspective, to be the real
difference. Then roughly estimating a mile at less than it really is,
also in courtesy to them, or at 5000 feet, we have this difference
between tints produced by 50,000 feet of air. Then, ten feet of air
will produce the 5000th part of this difference. Let the reader take the
two extreme tints, and carefully gradate the one into the other. Let him
divide this gradated shadow or color into 5000 successive parts; and the
difference in depth between one of these parts and the next is the exact
amount of aerial perspective between one object, and another, ten feet
behind it, on a clear day.

Sec. XXII. Now, in Millais' "Huguenot," the figures were standing about
three feet from the wall behind them; and the wise world of critics,
which could find no other fault with the picture, professed to have its
eyes hurt by the want of an aerial perspective, which, had it been
accurately given (as, indeed, I believe it was), would have amounted to
the 10/3-5000th, or less than the 15,000th part of the depth of any
given color. It would be interesting to see a picture painted by the
critics, upon this scientific principle. The aerial perspective usually
represented is entirely conventional and ridiculous; a mere struggle on
the part of the pretendedly well-informed, but really ignorant, artist,
to express distances by mist which he cannot by drawing.

It is curious that the critical world is just as much offended by the
true _presence_ of aerial perspective, over distances of fifty miles,
and with definite purpose of representing mist, in the works of Turner,
as by the true _absence_ of aerial perspective, over distances of three
feet, and in clear weather, in those of Millais.

Sec. XXIII. "Well but," still answers the reader, "this kind of error
may here and there be occasioned by too much respect for undigested
knowledge; but, on the whole, the gain is greater than the loss, and the
fact is, that a picture of the Renaissance period, or by a modern
master, does indeed represent nature more faithfully than one wrought in
the ignorance of old times." No, not one whit; for the most part less
faithfully. Indeed, the outside of nature is more truly drawn; the
material commonplace, which can be systematized, catalogued, and taught
to all pains-taking mankind,--forms