98 



brick-red. Some yellow flowers are not at all affected by 

 the acid. A yellow pansy quickly turns to a bright green, 

 followed by brick-red ; white flowers turn from pale to 

 chrome yellow. 



Salsoda changes some purples to bright blue, others to 

 bluish ; certain whites to lemon yellow, others to yellowish- 

 brown ; some yellows, as in Lysimachia, to brick-red ; this 

 last evidently contains some red, for it may be detected 

 with a lens. The soda brings it to view. 



Potash does not affect the yellow color of tulips, dande- 

 lion, or alamanda, but changes the lemon-yellow of oxalis 

 to blood-red ; it has no effect on the standard of Cytisus, 

 but changes its wings to a dull orange or amber color, and 

 Lysimachia to brick-red ; a purple crocus to green ; some 

 white flowers to lemon-yellow, others to bright red. A 

 scarlet pelargonium, it is said, changed by an alkali to 

 yellow, may be restored to its original color by an acid. 



The purple vegetable dye, litmus, changes to blue with 

 an alkali. 



Acids and alkalies are properties of plants ; various kinds 

 are free in the cell sap, and color is naturally influenced 

 accoi'ding to the proportions of each. 



Ordinary atmosphere changes the color of a certain mush- 

 room from yellow to blue when fractured, and the yellow 

 sap of Baptisia becomes an indigo-blue by simply agitating 

 it in the air. 



Ozone changes vegetable colors. 



Certain minerals, as iron, change colors. 



The action of the sun on the chlorophyl-green of stems 

 and leaves will often change that color to red or pur})le, 

 while the opposite side is unaffected 



Too strong sunlight will often destroy color or cause it 

 to fade to white, while a proper amount deepens it. 



Water will dissolve out certain purples, changing them 

 to white as in violets. 



Field scabious (Knautia) of two shades of iHir})le, is said 



