at our command, and with the assistance of the so-called 
chromatic circles and other appliances, can determine not 
only the exact position and shade of any given colour, but also 
the extent to which it is degraded or rendered impure, and 
though the general public very slowly adopts scientific terms 
and methods, still on the whole the tendency in our days is 
towards exactitude, and vague terms for objects and sensa- 
tions are more and more falling into disuse. 
2. In one respect the ancients must have laboured under 
the same disadvantage in determining the value of colour, 
as we moderns do. We very seldom see one colour 
alone, but generally two or more in juxtaposition, and con- 
trasted, and by contrast the effect of each colour on the 
human eye is considerably modified. Complementary colours, 
when seen in close proximity, heighten one another. Green 
next to red will appear much brighter than when placed 
close to blue. A colour of average purity will appear dull 
when compared with a brighter colour of the same hue, while 
it will seem, bright when seen alongside a more dingy shade, 
and so on. Unless great care be taken, therefore, we are 
liable to become inaccurate when describing a colour, though 
on the other hand, it may be doubted whether, if the human 
eye were so constructed as to see only one of the colours of 
the spectrum, we should from the absence of contrast be 
able to appreciate that colour correctly. 
To the fact that we almost always see colours in contrast 
must be ascribed the habit which men have of speaking of 
“ beautiful colours.” No one who has thought on the subject 
need be told thatasimple sensation cannot be strictly speaking 
beautiful. It is only by combination, contrast, and harmony 
of sensations that we arrive at beauty. To talk of a beauti- 
ful sound, such as a single note of a musical instrument, 
would be absurd ; it is only a combination of sounds that 
can be called beautiful. The terms “beautiful smell/ 1 
“beautiful taste,” would cause the most ignorant to smile, 
