128 
POPULAR SCIENCE REVIEW. 
vibrate in unison with that opposite and complementary 
colour, whatever it may be, that would, in conjunction with the 
original colour, make up white light. As we never see one 
absolutely pure colour completely separated from all others, 
this process is not simple, and the result does not consist in 
one primary and one complementary vibration, but in sets of 
both. This action is agreeable to the eye, and consequently 
a sense of harmony is created by the juxtaposition and simulta- 
neous contrast of colours that stand in this relation to each 
other. This is true, so far as relates to the primaries, which 
are conveniently considered as red, yellow, and blue,* or to the 
secondaries composed of any two of them. In the case of 
tertiary colours composed of various mixtures of the three pri- 
maries, we may start with disagreeable tints, and make them 
more so by this kind of contrast, or we may start with plea- 
sant tints and improve them, as the case may be. 
Many attempts have been made to compare colours with 
sounds, but only with partial success, although in both cases 
the numerical relations of the vibrations in one case to the 
optic, and in the other to the auditory nerves, determines 
whether sensations of pleasure or the reverse are produced. 
We may, however, use the terms colour harmony and colour 
melody in senses akin to those of the musician, though not 
precisely the same. Colour harmony is so far like sound 
harmony that it results from the simultaneous impression made 
by two or more colours seen at once, but it is not indispensable 
that the colours should, as it were, fuse together to the extent 
as the sounds do. In the harmony resulting from Chevreul’s 
simultaneous contrast, each colour, or component of the harmony, 
stands out distinct from the other component when the masses 
of each are sufficiently large. There are also colour harmonies 
in which no single hue or tone is allowed to acquire this pre- 
eminence ; the effect upon the eye is then analogous to the plea- 
sure received by the ear in listening to harmonies of a composer 
like Beethoven, rendered additionally complete by a fine 
orchestra comprising instruments varying in timbre or tone- 
clang. In a fine landscape it is often very easy to count 
twenty or thirty distinct tones and hues of rock, trees, heath, soil, 
&c., in rich harmony ; and when an artist attempts to render 
this with a few crude tints, the effect is little better than an 
attempt to play one of Mozart’s Masses upon a penny whistle. 
Colour melody may be used to mean something like tone 
melody, if we intend by it a succession of pleasurable effects in 
passing from one part of a picture, or artistic pattern, to 
* Green has a better claim than yellow to be regarded as a simple colour, 
but for art purposes the common way of speaking is the best. 
