22 
A NOMENCLATURE OE COLORS. 
It seems scarcely necessary to include the so-called 
gold and silver colors in the above classification, since 
they are nearly related, or at least analogous, to yellow 
and white respectively, the difference consisting chiefly 
in the existence of a metallic medium or surface. 
Observing the colors of the solar spectrum, it is obvious 
that each secondary color grades insensibly into the two 
primaries composing it, and that thus results an unbroken 
transition from one end of the series to the other. The 
transitions may be shown by the following sequence, 
the names of the primary colors being given in heavy- 
faced type (and also preceded by a Eoman numeral) and 
those of the secondary colors in italics. 
Spectrum Series, 
I. 1. Red. 
2. Orange-red. 
3. Eeddish orange. 
4. Orange. 
5. Yellowish orange. 
6. Orange-yellow. 
II. 7. Yellow. 
8. Greenish yellow. 
9. Yellowish green. 
10. Green. 
11. Bluish green. 
12. Greenish blue. 
III. 13. Blue. 
14. Purplish blue. 
15. Bluish purple. 
16. Purple. 
17. Reddish purple. 
18. Purplish red. 
Not only is the transition complete from nos. 1 to 18, 
but could the names be arranged in the form of a circle, 
