Hello Jeff,
Thank you for your answer.
I actually meant 2 scales on 1 single axis, such as in your first picture, but with two different scales, with one scale at the left of the axis, and the other one at the right on the axis. And then, at the right of the graph, a secondary axis. But maybe that is not possible in JMP, and then you don't see anything anymore...
Regards,
Lucie