362 SCIENTIFIC CONGRESS OF CARLSRUHE. 



this way amounts, in point of value, to something like two millions of 

 francs per annum. 



M. Kuhlmann proposes two modes of employing this residuum : one 

 by transforming it into chloruret of barium by means of carbon and 

 the sulphate of barytes ; the other by treating it with another embar- 

 rassing residuum of the soda manufactures, the oxysulphuret of cal- 

 cium, from which M. Kuhlmann obtains sulphide of manganese and 

 chloruret of calcium. 



The last mentioned chemist was followed by M. Schoenbein, the dis- 

 coverer of ozone, who, as he himself stated, has been occupied for 

 twenty years with the study of oxygen, and who furnished us, in the 

 results at which he has arrived, still another instance of the fact that 

 in science a noble reputation may be achieved even when the inquirer 

 restricts himself to the observation of a single body. We must observe, 

 however, that the new phenomena detailed to us on this occasion, im- 

 ply a degree of sagacity which doubtless does not fall to the lot of 

 every observer. 



Mr. Schoenbein began with informing us that there are three kinds of 

 oxygen, of which one, the common oxygen, is that which we respire 

 in the air. The two other kinds constitute two species of ozone, which 

 with reference to one another are as the two species of allotropic elec- 

 tricity, &c. We regenerate common oxygen when we place these two 

 species of ozone in contact, and, on the contrary, we destroy it when 

 by a given chemical agency we separate one of the two modifications. 

 This tendency, on the part of these two modifications, to produce com- 

 mon oxygen, explains certain effects called catalytic, and which had 

 till now remained unexplained; thus, the peroxyde of barium and 

 oxygenized water rendered acid by means of nitric acid, reciprocally 

 decompose each other in giving place to water, oxyd of barium, and 

 common oxygen: under the same circumstances, the permanganate of 

 potassium is reduced to manganic oxyd, the chromic acid becomes the 

 oxyd of chrome; that is to say, these compounds are deoxydized m 

 presence of an abundant supply of oxygen, and precisely at the con- 

 tact of that particular species of oxygen, ozone, whose burning power 

 is effectual to oxydize directly the least oxydizable bodies, such as 

 azote. 



Effects apparently so contradictory are to be explained by what we 

 have said above ; a combination highly oxygenized may be resolved in 

 presence of another compound rich in oxygen, whenever one of these 

 compounds contains oxygen which may be termed positive and the 

 other that which is negative. The result of such decomposition is 

 ordinary or neutral oxygen. A like result is had when we agitate 

 with oxygenized water ozone obtained with phosphorus ; the product 

 is nothing else but pure water, and common oxygen. 



That ozone, then, or nascent oxygen prepared with phosphorus 

 should act energetically as an oxydizer, it is not necessary that it 

 should be in presence of the oxygen arising from the oxygenized 

 water. 



Since, according to the experiments of M. Woelher, there is required 

 an equivalent of oxygenized water to decompose an equivalent of per- 

 oxyde of manganese, it may be said that, just as an acid loses its acid 



