158 SUBURBAN GARDENS 
its positive side is capable of most delightful 
development. 
As a general guide to the use of colors, it is 
well to fix the three primary colors in mind 
and the combinations which form the second- 
ary colors. The primary colors are pure yel- 
low, pure red, and pure blue, as of course 
everyone knows. These are “ primary ” be- 
cause they may not be further dissected into 
components, each standing by itself as a basic 
unit. They are the only colors that are thus 
distinguished. The secondary colors are scar- 
let, purple, and green, and these are each made 
up of two of the primary or basic colors, and 
no more, theoretically at least — yellow and 
red forming scarlet, red and blue forming pur- 
ple, and blue and yellow forming green. An 
actually pure color is almost unknown as a 
matter of fact and probably is unknown in Na- 
ture. For pure colors are not pleasant to the 
eye; their brilliancy needs tempering to make 
them endurable. 
Ordinarily two primary colors should not be 
used in groups that immediately adjoin, but a 
progression from one primary color to another 
by way of their secondary color, is always pos- 
sible and very effective if well carried out. 
Pure blue may progress to pure yellow by 
