The Positive Ray Analysis of Water Vapor Ionized by Impact of Slow Electrons

An electromagnetic method of separating gas ions of different mass, such as that used by Dempster, has been employed in a study of the ions produced by electron impact in water vapor. The principal ions appearing were ${\left({\mathrm{H}}_2\mathrm{O}\right)}^{+}$ and ${\mathrm{}\left(\mathrm{OH}\right)\mathrm{}}^{+}$. Of these the ${\left({\mathrm{H}}_2\mathrm{O}\right)}^{+}$ ions were more abundant. Unmistakable evidence was obtained that a third type of ion, probably ${\left({\mathrm{H}}_3\mathrm{O}\right)}^{+}$, was produced in very small quantities. ${\mathrm{H}}^{+}$ and ${\mathrm{H}}_2^{+}$ ions were always very few in number or unobservable. No ${\mathrm{}\left(\mathrm{OH}\right)\mathrm{}}^{-}$ or any other negative ions were observed.