Scientific American 2, 12.1.1861
Some interesting researches on vegetable coloring matters have lately been concluded by M. Filhol, of Paris. He has extracted the coloring matter from white flowers, and finds it to possess the following wualities: - It is a clear yellow solid, soluble in water, alcohol and ether, and furnishes very beautiful lake colors with metallic oxyds, and can be used for painting and dyeing fabrics of a bright and very durable yellow. It has been named xanthogene. The colors of red and blue flowers are found to be due to a similar proximate principle, which will be vlue in flowers with a neutral juice, and red or rose colored in those where the juice is acid. The name of this coloring matter is cyanine, a solid uncrystallizable body, soluble in water, and capable of being applied to many uses in painting. In yellow flowers two distinct coloring substances have been found, named respectively xanthine and xanthene. Another body, named crocoxanthine, is also met with in all the species of the genus Crocus. It is a solid uncrystallizable body, of a beautiful golden yellow color, which is neither altered by acids nor alkalies; it is soluble in water and alcohol, but insoluble in other; it produces, with some metallic oxyds, beautiful lake colors; and can be fixed upon fabrics, where its tinctorial power is remarkable. M. Filhol, in a memoir read before the Academy of Sciences, gives some valuable hintsa on the preservation of fresh flowers. We may proserve many flowers for a long time in a fresh state by enclosing them in sealed tubes. At the end of some days all the oxygen of the air confined in the tubes will have disappeared, and will have become replaced by carbonic acid. If we introduce into the tubes a little quicklime it removes from the flowers some of their humidity, which facilitates their preservation. Lime also takes up the carbonic acid, and the flower thus bedomes placed in pure nitrogen. All flowers are not preserved alike by this process; yellow flowers are those which are altered the least.