INTRODUCTION. 3 
come green, from yellower green to darker and bluer green. May 
green be reckoned the inicklle tint in Nature, as grass: it seems 
suited to our vision. It is not a little remarkable, that many 
subjects partake of the prismatic order of the colours of the sun 
or other luminaries, especially hemispherical ones, surrounded in 
a dark or perhaps aerial medium. Thus the evanescent tints be- 
come in effect realized in an admirable manner to our senses, taking 
due place in Nature to the fullest extent. 
I have only hinted at these things, that they may be enlarged 
upon if it should seem useful. Certainly, some fruits, such as 
peaches, pears, &c., have, occasionally, nearly if not all the tints 
allowed to the prism in due order upon them : thus the upper part, 
or the next under the leaf or stalk, is a full or crimson red, and 
this is often softened into orange ; yellow or yellowish succeeds ; 
then yellowish green ; then bluer, till the dull or under side par- 
takes of violet, especially if the warmer rays of an evening sun glow 
aslant on its downy coat, or help by their reflexion. Artists are 
generally aware of this in their paintings, and keep the warmer co- 
lours above and the colder ones below: even the warmer tints in 
Man, who walks erect and looks on Heaven, are seen most conspi- 
cuously in the upper part of his features. Indeed many artists con- 
sider the general light and warmer tints with the cold and shady 
sides (if I may so call them) of the rainbow, as a sort of rule to 
go by: the lighter side, to blend the colours of the lighter side of 
the subject, when the softening into the back ground would form a 
violet; a warm or reddish tint would come next, which would be 
blended by yellowish orange into the local tint, when the heightening 
would succeed ; next something of the local tint which would be- 
gin to recede into the yellowish and shade forming a grayish green ; 
then would succeed a darker shade with a violet tinge, and the rest 
would depend upon reflexion. Now these tints being judiciously 
managed, give a richness that is only understood by the artist who 
practises with such ideas. I have introduced the peach as an 
B 2 
