was stated that “the horizontal lines cast by clouds upon the sea are
not shadows, but reflections;” and that “on clear water near the eye
there can never be even the appearance of shadow.” This statement
being questioned in a letter to the _Art Union Journal_ (November,
1843), and that letter being itself criticised in a review of “Modern
Painters” in the _Artist and Amateur’s Magazine_, p. 262 (December,
1843), there appeared in the last-named periodical two letters upon
the subject, of which one was from J. H. Maw, the correspondent of the
_Art Union_, and the other--that reprinted here--a reply from “The
Author of ‘Modern Painters.’”
[187] The passages in “Modern Painters” referred to in this letter
were considerably altered and enlarged in later editions of the work,
and the exact words quoted are not to be found in it as finally
revised. The reader is, however, referred to vol. i., part ii., § v.,
chap. i., “Of Water as painted by the Ancients,” in whatever edition
of the book he may chance to meet with or possess.
[188] See the _Artist and Amateur’s Magazine_, p. 313, where the
author of the letter, to which this is a reply, adduced in support of
his views the following experiment, viz.: to put a tub filled with
clear water in the sunlight, and then taking an opaque screen with a
hole cut in it, to place the same in such a position as to intercept
the light falling upon the tub. Then, he argued, cover the hole over,
and the tub will be in shadow; uncover it again, and a patch of light
will fall on the water, proving that water is _not_ “insusceptible of
light as well as shadow.”
[189] In the review of “Modern Painters” mentioned above.
[190] Of the first edition of the first volume of “Modern Painters.”
The size of the book (and consequently the paging) was afterwards
altered to suit the engravings contained in the last three volumes.
[191] It may be worth noting that the optical delusion above explained
is described at some length by Mr. Herbert Spencer (“The Study of
Sociology,” p. 191, London, 1874) as one of the commonest instances of
popular ignorance.
[192] Of course, if water be perfectly foul, like that of the Rhine or
Arve, it receives a shadow nearly as well as mud. Yet the succeeding
observations on its reflective power are applicable to it, even in
this state.
[193] It must always be remembered that there are two kinds of
reflection,--one from polished bodies, giving back rays of light
unaltered; the other from unpolished bodies, giving back rays of light
altered. By the one reflection we see the images of other objects on
the surface of the reflecting object; by the other we are made aware
of that surface itself. The difference between these two kinds of
reflection has not been well worked by writers on optics; but the
great distinction between them is, that the rough body reflects most
rays when the angle at which the rays impinge is largest, and the
polished body when the angle is smallest. It is the reflection from
polished bodies exclusively which I usually indicate by the term; and
that from rough bodies I commonly distinguish as “positive light;” but
as I have here used the term in its general sense, the explanation of
the distinction becomes necessary. All light and shade on matter is
caused by reflection of some kind; and the distinction made throughout
this paper between reflected and positive light, and between _real_
and pseudo shadow, is nothing more than the distinction between two
kinds of reflection.
I believe some of Bouguer’s[194] experiments have been rendered
inaccurate--not in their general result, nor in _ratio_ of quantities,
but in the quantities themselves--by the difficulty of distinguishing
between the two kinds of reflected rays.
[194] Pierre Bouguer, author of, amongst other works, the “Traité
d’Optique sur la Gradation de la Lumière.” He was born in 1698, and
died in 1758.
[195] The mercury must of course be perfectly clean.
[196] Among other points, I have not explained why water, though it
has no shadow, has a dark side. The cause of this is the Newtonian law
noticed below, that water weakens the rays passing through its mass,
though it reflects none; and also, that it reflects rays from both
surfaces.
[197] The review of “Modern Painters” had mentioned the Grotto of
Capri, near Naples, as “a very beautiful illustration of the great
quantity of light admitted or contained in water,” and on this Mr. J.
H. Maw had commented.
[198] The _London Review_ of May 4 contained a critique of the
Exhibition of the Society of Water-colors, which included a notice
of Mr. Duncan’s “Shiplake, on the Thames” (No. 52). In this picture
the artist had painted a rainbow reflected in the water, the truth of
which to nature was questioned by some of his critics. Mr. Ruskin’s
was not the only letter in support of the picture’s truth.
[199] The present letter is the earliest in date of any in these
volumes.
[200] See note to p. 182.
[201] In the “Notes on the Turner Gallery at Marlborough House,”
1856 (p. 23), Mr. Ruskin speaks of the “pale ineffable azure” of the
gentian. The present letter was written in reply to one signed “Y. L.
Y.” in the _Athenæum_ of February 7, 1857, in which this expression
was criticised. In a subsequent issue of the same journal (February
21) Mr. Ruskin’s querist denied the ignorance imputed to him, and
still questioned the propriety of calling the gentian “pale,” without
at the same time distinguishing the two species.
* * * * *
Typographical errors corrected by the etext transcriber:
but their sensiblity to art=> but their sensibility to art {pg 27}
whatever space was sacrified to it=> whatever space was sacrificed to it
{pg 50}
Admitedly it contains the finest=> Admittedly it contains the finest {pg
111}
thirteenth or fourteeth century=> thirteenth or fourteenth century {pg
148}
and naturally eneugh=> and naturally enough {pg 165}
betwen their agencies=> between their agencies {pg 176}
End of Project Gutenberg's Arrows of the Chace, vol. 1/2, by John Ruskin