Axes tab
The Axes tab is a tab of the Format Data Series dialog box. See Formatting data series.
On the Axes tab, you specify whether a data series is plotted on the Primary axis, or on a secondary axis.
A chart can contain two sets of data. For example, automotive magazines often contain charts which compare Horsepower and Torque. In this case, horsepower might be plotted against the Primary axis and torque against a secondary axis.
To enable a secondary axis: