178 Prof. J. D. Forbes on the Classification of Colours. 



scarcely sensibly differing from each other. This last circum- 

 stance was probably occasioned by the carelessness and indo- 

 lence of the workmen who selected them. The former cir- 

 cumstances might naturally be expected in a collection con- 

 structed for the purpose of imitating paintings, in which, as is 

 well-known, optically pure colours are almost never used ; but 

 their effect is invariably produced by skilful contrasts. Many 

 of the suites of indefinite colours are exquisitely beautiful. 

 With Mr. Hay's assistance, I selected a sufficient number of 

 distinct hues to represent tolerably Mayer's triangle of colours; 

 but the great mass of colours being only detached suites, it was 

 impossible to combine them into a connected whole. As I have 

 no doubt, however, that the collection is one which faithfully 

 represents the colours chiefly used by artists, it may not be 

 uninteresting to copy the catalogue forwarded to me by Mon- 

 signore Spada, with the local names and the principal denomi- 

 nations on the scale of nomenclature proposed in this paper, 

 which they include. 



Local Names. Technical Names. 



100 specimens. Bigi. Tints of yellow-gray, and tints of gray. 



100 ... Cabnagioni. Tints of orange-gray [brown], reddish- 



yellow gray, reddish-purple gray, purple- 

 gray. 

 60 ... GiALLi. Tints of yellow-gray and reddish-yellow 



gray. 

 Orange passing into red and yellow. 

 Grayish-red, reddish-gray, yellowish-gray, 



purplish-gray, shades of piuplish-gray. 

 Yellow-gray passing into purple-gray, 



shades of purple-gray. 

 Gray-purple and tints of ditto. 

 Red and grayish-red. 

 Tints of yellow, tints of orange, tints of 



yellow-gray and of red-gray. 

 Tints of blue, tints of purplish-blue, gray- 



ish-greenish blue. 

 Tints of green-gray, tints of blue-green. 



This number of specimens would have been sufficient to 

 make a complete series of colours ; but, as has been said, they 

 were very deficient in the more positive hues. I have still 

 hopes, however, of being able to obtain a series of perfect 

 matches for the whole series of Mr. Hay's pigments, speci- 

 mens of which have indeed been already sent to Rome for the 

 purpose. 

 Edinburgh, January 1849. 



