On The Effect of the Medium on Gas Ion Mobility

Effect on the mobility of air ions of adding varying amounts of C${\mathrm{O}}_2$, ${\mathrm{H}}_2$, water vapor, ${\mathrm{C}}_2$ ${\mathrm{H}}_2$, ${\mathrm{C}}_2$ ${\mathrm{H}}_4$, ${\mathrm{Cl}}_2$ and N${\mathrm{H}}_3$ to the medium.—In this paper results are given showing the effect on the mobility of adding foreign gases to the air through which the ions move. The conditions were such as to permit the use, at least initially, of identical air ions. It is shown that adding C${\mathrm{O}}_2$ and water vapor to the air diminishes the mobility but adding hydrogen increases the mobility. The results also indicate that the change in the mobility is due to the change in the medium and not to a change in the ions. It is however found that increasing the relative humidity gives a larger proportion of initial or 1.87 ions indicating that ${\mathrm{H}}_2$O simplifies the final positive air ion. It is also shown that a trace of acetylene gives rise to an ion which has a mobility only slightly less than the initial air ion. It was also found that when acetylene remains in air a body is formed which when it becomes charged has a lower mobility.