igo The Lines of Discovery in the [March, 
this ozone after drying still contained the elements of water 
or hydrogen. 
Three hundred litres of the desiccated air were passed 
through a narrow glass tube heated to redness, in order to 
decompose the ozone, and then through a second sulphuric 
acid drying tube. Since the latter in repeated experiments 
showed no increase of weight, Schonbein regarded the 
absence of hydrogen in ozone as conclusively proven. At 
the same time he did not accept the views of Marignac and 
De la Rive, declaring that to him the existence of an 
allotropic modification of a gaseous body was inconceivable. 
For a long time, however, the theory that ozone was a 
compound of hydrogen and oxygen prevailed. It derived 
great weight from the experiments which had been made by 
Williamson in 1845. He prepared ozone by electrolysis, 
and to avoid obtaining any hydrogen along with the electro- 
lytic oxygen, used oxide of copper dissolved in sulphuric 
acid as the electrolyte. The gas was dried over calcium 
chloride, and then passed over ignited copper turnings into 
a second drying tube : this uniformly showed an increase 
of weight. The copper previous to ignition had been reduced 
by carbonic oxide, and not by hydrogen, in order to pre- 
vent the possibility of any occluded hydrogen being given 
up, on ignition, to the stream of ozonised oxygen. 
These views were apparently confirmed by Baumert’s 
experiments (1853). He passed the electrolytic oxygen 
evolved in such a manner as to exclude the presence of 
hydrogen, through a very long sulphuric acid drying tube, 
and thence into an absorption apparatus containing potas- 
sium iodide and provided with a sulphuric acid bulb-appa- 
ratus, to condense evaporated water. In case the matter of 
ozone and oxygen were identical, the weight of oxygen 
equivalent to the weight of iodine set free by the ozone 
should have been equivalent to the total gain in weight by 
the absorption apparatus. But, according to the experi- 
ments, this weight was less, and the numbers found appa- 
rently assigned to electrolytic ozone the formula H 2 0 3 . 
And since Baumert found that ozone prepared by the 
ekCtric discharge could not be made to yield up the elements 
of water on strong heating, while that prepared by electro- 
lysis could, he regarded the two as different bodies — the 
former as allotropic oxygen, the latter teroxide of hydrogen. 
Thus the old hypothesis, against which Schonbein had so 
long striven, that there were two (and possibly more) bodies 
of the nature of ozone, was rehabilitated. It was finally 
overthrown by Andrews (1856), who showed that the 
