Thesis
presented for the attainment of
the degree of Doctor of Philosophy
at the Johns Hopkins University.
by
Edward H. Keiser.
Baltimore,
1884
That a gaseous element can exist in an allotropic condition was firstclearly shown by a careful study of the properties of ozone. Althoughdiscovered by Schönbein in 1840, chemists were for a long time unableto determine its true nature, and it was not until seven years laterthat Marignac[1]succeeded in proving that it was oxygen in an allotropic condition.[Pg 4][Pg 5]Marignac’s work was confirmed by De la Rive, and subsequently theelaborate researches of Andrews and Tait, and Soret, as well as thoseof von Bato and Claus have established beyond all question that ozoneis an allotropic modification of oxygen, and that its density is oneand a half times that of ordinary oxygen.
The possibility of the existence of allotropic modifications of oxygenhaving been thus established it is not surprising that attempts shouldhave been made to find other forms in which this element might occur.As early as 1855 Houzeau[2]stated that when barium superoxide was decomposed with concentrated[Pg 6][Pg 7]sulphuric acid, at low temperatures, a colorless gas was evolved whichoxidized metals and ammonia. It had a penetrating odor and possessedthe power of bleaching litmus paper, and liberated iodine frompotassium iodide. By heating the gas to a temperature of 75°C it wascompletely converted into ordinary oxygen. He calls the gas nascentoxygen and further states that it is probable that whenever oxygen isset free from any of its compounds at low temperatures it is in thenascent or active state.
Clausius[3]at one time supposed that free atoms of oxygen might exist in an uncombined[Pg 8][Pg 9]state, and his hypothesis on the nature of ozone was that thissubstance consisted of a mixture of molecules and free atoms of oxygen.In a later paper[4],however, he abandoned this view and regarded ozoneas consisting of one or more atoms of oxygen feebly united, (loseverbunden) with molecules of ordinary oxygen.
The idea that a third form of oxygen existed also obtained support fromthe fact that certain organic substances when exposed to the light inthe presence of oxygen or air, acquire oxidizing properties. In 1850Schönbein[5]stated that ether turpentine, and oil of lemons if allowed[Pg 10][Pg 11]to stand in diffused light in contact with the air acquires thepower of decomposing potassium iodide, and decolorizing indigo. In asubsequent paper[6]he shows that methyl and ethyl alcohols, tartaric and citric