20 INTRODUCTION. 



OF THE COLOUR OF FLOWERS. 



Colours are said to be the gift of light, or of 

 the form of tlie reflecting surfaces, or rather of 

 the position of the atoms which compose the 

 surfaces of bodies. The same substances reflect 

 different rays of light according as they are 

 changed in position, exterior form, or constitu- 

 tional texture. Natural productions are variously 

 composed, and accordingly reflect almost all the 

 various rays which compose the stream of light. 

 Hence the variety of the chromule, or colours of 

 flowers, and of the different shades of colour in 

 the same flower. And though the substance of 

 a variegated petal appears to the eye as perfectly 

 uniform in its texture, and though no microsco- 

 pic assistance can detect the difference in the 

 coloured matter, yet we may be certain that a 

 difference exists, and also that it is a transferable 

 quality. The least pressure or touch on a de- 

 licate vegetable body instantly changes, in some 

 cases, one tint to that of another. 



