286 ANNUAL OF SCIENTIFIC DISCOVERY. 



Now, a general fact is this, that the oxygen thus set free always contains 

 traces of ozone, more or less according to the degree of temperature at which 

 the oxygen happens to be disengaged from those compounds. The lower that 

 degree, the larger the quantity of ozone mixed with the oxygen; though in. 

 all cases the quantity happens to be exceedingly small in comparison with that 

 of the oxygen obtained at the same time. The best means of ascertaining the 

 presence of ozone is the alcoholic solution of guiacum recently prepared. 

 Oxygen does not in the least change the color of that resiniferous liquid, 

 whilst ozone seems to possess the power of coloring it deep blue. The blue 

 matter is nothing but guiacum plus ozone. Now, if we heat the purest oxide 

 of gold, platina, silver, mercury, the peroxides of lead, manganese, &c., in fact 

 any substance yielding oxygen, within a small glass tube, into which had been 

 previously introduced a bit of filtering paper impregnated with guiacum solu- 

 tion, the paper will turn blue as soon as the disengagement of oxygen begins. 

 All the circumstances being the same, the paper will be colored most 

 deeply by the oxygen eliminated from that compound which requires the 

 lowest temperature for yielding part or ah 1 of its oxygen. 



Mr. Schoenbein further goes on to say that there cannot be any doubt that 

 all the oxygen contained, for instance, in the oxide of silver, previous to that 

 compound being decomposed by heat, exists in one state be that state what 

 it may. But how then does it happen that two different sorts of oxygen are 

 generated at the same time from one compound ? The answer to this seems 

 to be, that one of the two kinds of oxygen eliminated must be engendered at 

 the expense of the other ; or to speak more correctly, that during the act of 

 elimination of oxygen from the oxide of silver, part of that oxygen suffers a 

 change of condition. Now, as the oxides of gold, silver, &c., possess the 

 power of coloring blue the guiacum solution, just as free ozone does, it is 

 considered that the condition of the oxygen contained hi the oxides of gold, 

 silver, &c., is the ozonic one ; and it is further inferred, that by far the great- 

 est portion of that ozone under the influence of heat is transformed into 

 oxygen. 



Now certain species of mushrooms contain a colorless principle easily 

 soluble in alcohol, and in its relations to oxygen bears the closest resemblances 

 to guiacum, as appears from the fact, that all the oxidizing agents which 

 have the property of blueing the alcoholic solution of guiacum, also enjoy the 

 property of coloring blue the alcoholic solution of the mushroom principle ; 

 and the deoxidizing substances which decolorize the blue solution of the 

 guiacum, also discharge the solution of the mushroom principle. 



The resinous principle of the mushroom does not seem to possess the 

 power of coloring itself, except so long as it is in contact with the paren- 

 chyma of the plant. This has led Schoenbein to the discovery, that there 

 exists in the mushroom a principle which possesses the property of exalting 

 the chemical power of oxygen, and of causing it to combine in the ozone 

 condition with the resinous principle. In many respects this compound 

 appears to resemble the binpxide of nitrogen, and its existence confirms an 

 opinion before expressed by Schoenbein, that the oxidizing effects of atmo- 

 spheric oxygen (of itsolf inactive), which are produced upon organic bodies, 



