200 ANNUAL OF SCIENTIFIC DISCOVERY. 



small proportion of a sulphtiret, of which the glass before insolation 

 shows no trace. The metalloids, charcoal, silicium, boron, phos- 

 phorus, and even hydrogen, color glass yellow, reducing the alka- 

 line sulphate which it always contains to sulplmret; these deoxi- 

 dizing substances have no effect on glass free from iron and from 

 sulphate. 



Faraday, in 1822, drew attention to the violet and purple tints 

 produced in window-glass by the action of the sun. Pelouze 

 (1867) states that this coloration is found in glass which contains 

 both oxide of iron and oxide of manganese. When a batch of 

 glass threatens to be too dark-colored for sale, the workmen add 

 " glassmaker's soap," or binoxide of manganese, in such quantity 

 that all the iron passes to the maximum, and all the manganese to 

 the minimum of oxidation ; the glass is thereby whitened, since 

 the protoxide of manganese does not color it, and the peroxide of 

 iron tinges it much less than the protoxide. All his specimens, 

 thus colored by the sun, become un-colored by the action of a dull 

 red heat, or that required for annealing; the glass rendered color- 

 less by heat again becomes tinted on exposure to the sun, loses 

 the color on reheating, and so on repeatedly. 



M. Bontemps, in " Comptes Rendus," Feb. 4. 1867, attributes 

 the yellow coloration of glass by the sun to the presence, not of 

 oxide of iron, nor of sulphate of soda, but of oxide of manganese. 

 The violet coloration of glass, alluded to by Faraday, he attributes 

 also to manganese, and explains the difference in coloration by the 

 fact that insolation colors glass with a potash base violet, and glass 

 with a soda base yellow. 



OZONE AND 'ANTOZONE. 



The Abbe Moigno, in Dec., 1845, soon after the publication of 

 Schonbein's observations, wrote to the " Epoque," as follows: 

 " It is necessary to return immediately to the ideas of Ampere, 

 and consider the atoms of bodies as having two states, first, 

 with the essential primitive electricity, or in a nascent state ; sec- 

 ond, with their electricity more or less disseminated, or their at- 

 mosphere of electricity in a neutral state. The ozone of M. 

 Schonbein is, in our eyes, only a molecule of oxygen in a nascent 

 state, with only negative electricity in its atmosphere." In July, 

 1847, in the " Nouvelle Revue Encyclopedique," he says more 

 explicitly: "Sufficient attention has not yet been paid to the 

 important fact that oxygen disengaged by plants is not in a neu- 

 tral state. We are perfectly convinced that this nascent oxygen, 

 without its positive atmosphere, is the ozone discovered by M. 

 Schonbein, with an odor sui generis, and possessing, in the highest 

 decree, all the properties of electro-negative substances." He 

 claims to have, therefore, first made known the nature and appli- 

 cation of ozone. 



According to M. Soret, of Geneva, the density of ozone, as ob- 

 tained in absorption experiments, is li \\mes that of oxygen. He 



