§ 46. PRIMARIES AND SECONDARIES. 67 



with water : " but the particular hue of yellow, blue, red, 

 crimson, and scarlet, and some other colours, implied whenever 

 I mention them, may be seen in Plate in. fig. 5. Yellow, 

 Mr. Field remarks, " is less diminished than all other colours, 

 except white, by distance," and has a great power of reflecting 

 light. It displays itself very evidently in all the varieties of 

 bright green and orange; and the hues of canary, lemon, 

 buff, drab, chesnut, and various light browns, tawny, hazel, 

 and others, are chiefly indebted to it for their composition as 

 well as for their brightness. 



To this first class, some have added black and white ; ex- 

 tending the number of the primaries to five ; but their not 

 being among those of the prism may exclude them from a 

 place both in the first and second class. 



Mengs observes, that " colours properly speaking, are but 

 three," yet " as we cannot do without black and white," he adds 

 these to the primary colours, and extends the number to five ; 

 and Leonardo da Vinci says, " the first of all simple colours 

 is white, though philosophers will not acknowledge white and 

 black to be colours, because the first is the cause and receiver 

 of colours, the other totally deprived of them. But as painters 

 cannot do without either, we shall place them among the 

 others : and according to this order of things, white will be the 

 first, yellow the second, green the third, blue the fourth, red 

 the fifth, and black the sixth." It is, however, inconsistent to 

 admit green, and exclude purple and orange ; and Mayer and 

 others are right in limiting the number of primaries to three : 

 blue, red, and yellow. 



B. The secondaries are compounds of any two of the three 

 primaries ; of blue and red ; of yellow and red ; or of yellow 

 and blue : making purple, orange, and green. But it is not 

 easy to define their exact hues unless we limit them to the 

 product of equal parts of two primaries ; and for these, I 

 must again refer to Plate III. fig. 5, and to Sect. XIX. ; which 



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