THE 

 LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 



[THIRD SERIES.] 

 MARCH 1849. 



XXI. Hints toiscards a Classification of Colours. 

 By Professor J. D. Forbes*. 



TO classify and describe colours is not so easy a matter as 

 it might at first sight appear to be; and yet it is of very 

 considerable interest, as well scientific as artistical. It is im- 

 possible that this shall be completely done until we understand 

 far better than at present the cause of the colours of bodies, 

 natural or artificial. Had Newton's explanation of these 

 colours been as satisfactory as it was for the phagnomena of 

 the solar spectrum, the classification of colours would be more 

 simple and obvious than it is. My present object is to treat 

 the subject not at all as a matter of art, neither as to the effect 

 which colours produce in painting as an imitative art, nor as 

 to the chemical art of producing and combining pigments ; but 

 simply as a matter of description and nomenclature, so that 

 the objective effects of varied lints and hues may be referred 

 to some standard classification of colours and their modifica- 

 tions. I shall then state what progress I have made in form- 

 ing such a stantlard suite of colours. 



I am unable, and have not the intention, to give a complete 

 history of the principles and methods adopted at different 

 times for classifying and compounding colours for the use of 

 the painter, and in imitation of natural hues which probably 

 exhaust all which art can succeed in producing. For what I 

 shall now state I am in part indebted to the ingenious essay 

 of the profound Lambert, called Beschreibung einer Ausge- 

 mahlten Farbenpyramide-\. 



Pliny, in describing the pigments used by the most famous 

 painters in their pictures, mentions four, which, according to 



* Communicated by the Author having been read before the Royal 

 Society of Edinburgh, December 4, 1848, and January 15, 1849. 



t 4to. BerUn, 1772. 

 Phil, Mag, S. 3. Vol. 3*. No. 228. March 1 849. M 



