DO now CnOPS FEED. 



Allotropism.— This occurrence of nn element in two or even 

 .oore forms is not witliout otlier illustrations, and is termed Allotropism. 

 Pliosphorus occurs in two conditions, viz., red pliosphorus, which crys- 

 tallizes in rhonibohedrons, and like ordinary oxyjjen is coiniiaratively 

 inactive in its affinities; and colorless phosphorus, which crystallizes in 

 octahedrons, and, like ozone, has vigorous tendencies to unite with ottier 

 bodies. Carbon is also found in three allotropic foims, viz., diamond, 

 plumbago, and charcoal, which diflfer exceediugly in their chemical and 

 physical characters. 



Ozone Formed by Chemical Action. — Not only is ozone 

 produced by electrical disturbance, but it has likewise 

 been sliown to originate from chemical action ; and, in 

 fact, from the very kind of action which it itself so vig- 

 orously manifests, viz., oxidation. 



When a clean stick of colorless phosphorus is placed at 

 the bottom of a large glass vessel, and is half covered 

 with tepid water, there immediately appear white vapors, 

 which shortly fill the apparatus. In a little time the pe- 

 culiar odor of ozone is evident, and the air of the vessel 

 gives, with iodide-of-potassium-starch paper, the blue color 

 which indicates ozone. In this experiment ordinary oxy- 

 gen, in the act of uniting with phosphorus, is partially 

 converted into its active modification ; and although the 

 larger share of the ozone formed is probably destroyed by 

 uniting with phosphorus, a ])ortion escapes combination 

 and is recognizable in the surrounding air. 



The ozone thus developed is mingled with other bodies, 

 (phosphorous acid, etc.,) which cause the white cloud. 

 The quantity of ozone that appears in this experiment, 

 though very small, — under the most favorable circum- 

 stances but ' |j3„„ of the weight of the air, — is still sufficient 

 to exhibit all the reactions that have been described. 



Schuiibein has shown tliat various organic bodies which 

 are susceptible of oxidation, viz., citric and tartaric acids, 

 when dissolved in water and agitated with air in the sun- 

 light for half an hour, acquire the reactions of ozone. 

 Ether and alcohol, kept in partially filled bottles, also be- 

 come capable of producing oxidizing efiects. Many of the 



