COLOR OF PLANTS AND FLOWERS. 45 



iron in a low state of oxidation be the coloring substance 

 of a flower, it is clear that as soon as the juice of the 

 plant becomes more acid, a farther oxidation takes place, 

 this would cause a change in color." 



" I would instance the Lilac. Iron in a low state of oxi- 

 dation combined with manganese and carbonic acid, form 

 component parts of a mineral called Pearl-spar, which is 

 of a brilliant white — it may therefore exist in the same 

 state in the white Lilac ; and the manganese is often found, 

 particularly in the Tiree marble, to be the cause of lilac 

 color — as the juices ripen and grow more acid, the iron is 

 farther oxidized, the flowers fade, turn of a rusty brown, 

 and finally the seed vessel ripens of a dark brown." 



That Iron is able to produce almost every variety of 

 color we may learn from the fact that the native miner- 

 als. Phosphate of iron is of all shades of blue. Sulphate 

 and arseniate of iron, are green, brown, yellowish red, 

 brownish green. Humboldtine or oxalate of iron is bright 

 yellow, etc., etc. 



Manganese is also found of most colors, from the green- 

 ish blue of the Horn Mangan to the rose red of the Tiree 

 marble. 



" The amethyst is supposed to be colored by iron and 

 manganese, the emerald by oxide of chrome; the topaz, 

 the sapphire and the ruby by iron." 



" It is well known to the florist that over manured soil 

 deepens, or spoils, as he calls it, the colors of his tulips and 

 other favorites, and that from this deterioration it is difii- 

 cult to recover them. 



" Strong manure contains a large proportion of alkah, 

 and this always deepens and rather deadens many colors, 

 particularly of the red and purple tinge, while acids on 

 the contrary lighten and enliven them ; this consideration 

 may be experimentally applied to the subject.'' 



A number of years since I sold to a Tulip amateur a bed 



