70 ON COLOUR. Paet I. 



C. The tertiaries have also been reckoned as three: russet, 

 citrine, and olive. 



D. But there are others which require to be arranged in 

 a separate class distinct from the primaries, secondaries, and 

 tertiaries, as browns, greys, and various neutral tints (into 

 which black often enters as a principal element), together 

 with clay and stone colours, drab and others. These neces- 

 sarily form a fourth class, and I have called them, by way of 

 distinction, "Irregular colours." They have also received 

 the name of " semi-neutral." Many of them are very varied 

 in their hues. Browns, for instance, have sometimes a deep 

 sombre character ; others are brighter in proportion as they 

 have more red or more yellow in their composition, e. g. ches- 

 nut, &c. ; and red-browns, yellow-browns, and purple-browns 

 designate certain varieties, all of which hold a place among 

 warm colours. For whenever such a quantity of blue is 

 added as to deprive brown of its warmth, it passes into another 

 grade of hues, and approaches the greys. Of browns, the 

 "chief constituent" is said to be "yellow;" and they are 

 considered to be compounded of yellow and black ; of black, 

 red, and yellow; of black and orange; of blue, red, and 

 orange; of the three primaries — red, blue, and yellow; or of 

 the three secondaries, or of the three tertiaries, the richer 

 browns having more red and yellow, and the lighter browns 

 being sometimes diluted with white. But brown is also com- 

 pounded of red and black ; and it is inconsistent to maintain 

 that red does not enter into the composition of brown, and at 

 the same time to admit that it is partly compounded of 

 orange — a colour of which red is a constituent. Again, black 

 and red form a better brown than most of those above enume- 

 rated; black and yellow giving a very imperfect brown, and 

 rather partaking of an olive mixture ; and a similar objection 

 may be made to blue, red, and yellow, and their derivatives. 



Greys are composed of black and white. Other combina- 



