Ozone and the Atmosphere. 217 



upon flowers. It is well known that indigo solution, poured 

 into a bottle filled with ozone, is instantly bleached. In this 

 case the colorless modification of indigo is formed. But attempts 

 hitherto made to destroy the coloring matters of plants by ozone, 

 have yielded in our hands negative results. These results are 

 striking as compared with those obtained by a reducing agent 

 like sulphurous acid, or with chlorine. 



A light red rose was exposed for three hours to a current of 

 2>\ litres of ozonized oxygen, containing a little more than 1 

 mgrm. ozone per litre. JSTo effect was discernible on either 

 leaves or flower. In sulphurous acid, it was bleached in the 

 course of a few moments, though the chlorophyll of the leaves 

 was unaffected. Returned to the ozone, the blanched petals 

 reddened, showing that the sulphurous acid with which they 

 were impregnated had been ozonized. The same effect was 

 produced by dilute sulphuric acid. 



An abutilon, a yellow and a blue pansy, cineraria, red ger- 

 anium, fuchsia, hyacinth, pink, violet, and heliotrope, were ex- 

 posed for 18 hours, in a quart bottle filled with ozone. On 

 opening the bottle, no smell, except the perfume of the flowers, 

 was apparent, and none of the flowers had changed except the 

 violet and heliotrope. These had turned slightly brown, due 

 probably to natural wilting. Other specimens of the same 

 flowers were placed in an atmosphere containing sulphurous 

 acid. The heliotrope began to change immediately, and in ten 

 minutes its color had entirely disappeared. The hyacinth fol- 

 lowed, and in the same length of time, only streaks of red 

 remained. The bouvardia was nearly white; the fuchsia, 

 japonica, geranium, and cineraria were somewhat bleached • 

 the yellow pansy not noticeably affected. At the end of 34 

 hours, the darker portion of the fuchsia was nearly bleached 

 the geranium had become pink, the blue pansy was of a yellow 

 color somewhat darker than the yellow pansy, the abutilon still 

 unchanged. Flowers of Salvia splendens, Camellia Japonica 

 (red), Strelitzia regina, Abutilon venosum, Abutilon insigne 

 Inga pulcherrima, lxia, Cineraria, Nasturtium, Azalea 

 Indica, and Bouvardia, were exposed for 36 hours to ozonized 



