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CHEMISTRY: G. L. WENDT 
considerable quantities of in an H2 tube. At pressures of 0.05 mm., 
indeed, Dempster has shown that H3 predominates. 
Very recent work has shown that this active hydrogen is present 
in large quantities in any ordinary hydrogen discharge tube. A Geissler 
tube under a pressure as high as 6 cm. contains the ozone hydrogen. If 
hydrogen is passed continuously through such a tube and is then 
allowed to react with sulfur a lead acetate paper is decidedly blackened 
in the course of two or three minutes. Potassium permanganate is de- 
colorized with equal speed. This is an effective lecture experiment. 
No ions are present in this hydrogen, as can readily be shown by passing 
the gas through a sensitive emanation electroscope. When this instru- 
ment is sensitive enough to detect 10-12 Curie of radium emanation 
with ease, the electroscope leaf remains perfectly steady though the 
active hydrogen is passed through for hours. The activity is therefore 
due to molecules. 
The mechanism by which these larger and unstable molecules are 
formed is still obscure. In the case of their formation under the action 
of alpha rays they may be the product of the bombardment of ordinary 
hydrogen molecules by means of the swift and very energetic alpha 
particles. A hydrogen atom thus projected by bombardment into an 
ordinary hydrogen molecule may remain there in the metastable con- 
dition of a triatomic molecule. The formation of this variety of 
hydrogen, however, in the cathode ray discharge tube, where the only 
bombardment is by a stream of electrons, indicates that probably 
nothing more than ionization is necessary. The most plausible h3rpoth- 
esis is that the ions collect about them a cluster of molecules, forming 
a so-called large ion, and that the valence bonds in such a group are so 
disintegrated that the cluster breaks down with the formation of various 
types of fragments, among them H3 as well as H2. Cluster ions are 
undoubtedly present in such a tube, though their quantity is hard to 
estimate. Dempster has shown, however, that at low pressures both 
II3 and H2 are present in large quantities, with H3 predominating in 
certain ranges of pressure. Still more information on the mechanism 
of the formation of this type of molecule would be obtainable from a 
study of the action of very short wave-length light on hydrogen. The 
Schumann region of the spectrum is absorbed by hydrogen, and the 
ionization or molecule shattering that probably then occurs may also 
give rise to this ozone form. This phase of the question is now being 
investigated. 
The existence of such a molecule as H3 does not accord with the present 
theories of valence. The univalence of hydrogen is the basis of the 
