PRODUCED BV ELECTRO-CHEMICAL ACTION. 115 



colours to the other through the intermediate tints, the first feehng 

 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 

 ochi-es, 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 and a 

 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 circumstances. 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 tiiey differ greatly in brightness. The clearest of them is the 

 yellow. Fraunliofer, who has analysed the spectrum with so much care, 

 assigns to that colour the highest degree of brightness. 



The tints of our scale as well as the natural colours are far from being 



i2 



