How to Overlap Two Different Line Graphs for Comparision?

Hello,

I am new to the Visual Studio (2019) Forms Chart tool. I have two line graphs that show a correlation between them. I would like to compare both line plots together but they don't overlap on the same graph. One graph plots temperature over time and the other plots quantities of gases over time. The values for temperature are all negative and the values for gases are all positive.

I tried overlapping two Chart Areas with transparent backgrounds, but when I set both Chart Areas to the same size and location, nothing from the second Chart Area is visible at all. I have tried setting the Chart background, the Chart Area background and even the Series background transparent.

chart1.BackColor = Color.Transparent;
chart1.BackSecondaryColor = Color.Transparent;
chart1.ChartArea[0].BackColor = Color.Transparent;
chart1.ChartArea[0].BackSecondaryColor = Color.Transparent;
chart1.Series[0].BackSecondaryColor = Color.Transparent;

The only change I saw was the visible graph background changed from white to the off white color of the Form window background. I can see both graphs fine when they are not overlapping, so there is no problem there.

Is this possible to achieve or is there a different solution to overlap two line graph plots of different data types?

Thank you kindly.