PRODUCED BY ELECTRO-CHEMICAL ACTION. 115 
colours to the other through the intermediate tints, the first feeling 
will be changed into an agreeable sensation. Our scale, I repeat it, 
produces the same agreeable impression upon all, and it is to the inimi- 
table beauty of its colours, and the manner in which they melt into each 
other, that this effect is due. 
According to the law of imaginary colours red harmonizes well with 
green. In our scale the lakes, which are the finest reds in nature, are 
between the green tints and the orange, and combine agreeably with 
both. According to the same law the violet should agree only with the 
yellow; in the scale the violet tints are between the azures and the 
ochres, where they produce a very fine effect. The same law is opposed 
to the combination of yellow and azure, but the scale proves that these 
two tints combine agreeably, provided they have a certain tone anda 
certain degree of brightness. It is unnecessary, I believe, to multiply 
instances. The beauty of the tints and the graduation of the transitions 
constitute together one of the first secrets of art revealed by the effect 
of the chromatic scale. But it is not always allowed us to resort to the 
graduation of the transitions, and the artist requires another guide to 
show him what he is to do in all cireumstances. It cannot be doubted 
that as there are combinations of sounds more perfect to the ear than 
others, such as the octave, the fifth and the third, there are likewise con- 
cords of colours more pleasing to the eye than others. But these con- 
cords should be determined. The field of inquiry is still new; it is 
possible however that the pursuit may be attended with most success 
by having recourse to the chromatic scale, which presents the tints in 
their greatest purity, and so arranged as to form the gamut of colours. 
This circumstance is an additional recommendation of the scale to the 
attention of philosophers as well as of artists. 
Concluding Reflexions on the Qualities of Colours considered both philo- 
sophically and pictorially. 
In physics it is usual to speak only of the brightness of colours. But 
besides being more or less bright, they are more or less intense or deep, 
beautiful, cheerful, &c. These epithets have been long in common use 
and are constantly on the lips of painters. In my opinion it is time 
that they should be admitted into science, and reduced to a more deter- 
minate signification than they have in ordinary language. 
Brightness. 
All who observe the seven colours of the spectrum will instantly per- 
_ ceive that they differ greatly in brightness. The clearest of them is the 
_ yellow. Fraunhofer, who has analysed the spectrum with so much ae; 
_ assigns to that colour the highest degree of brightness. 
‘The tints of our scale as well as the natural colours are far from being 
12 
