[Cybiote]

These are known as https://en.wikipedia.org/wiki/Parallel_coordinates and are a pretty old technique. Although the wiki lists process control as one of the major users, their history has them as dormant until revived in their modern form in the 1960s, which doesn't quite match your timeline. Perhaps the discrepancy is resolved by whether parallel axes were used as a equation solving aid versus a visualization aid?

They're also not outdated, you can find them in many libraries, like highcharts here: https://www.highcharts.com/docs/chart-and-series-types/paral...

Excellent technical coverage is: Parallel Coordinates for Visualizing Multi-Dimensional Geometry, from 1987 at https://link.springer.com/chapter/10.1007/978-4-431-68057-4_...

Wikipedia links to this 1880 chart: https://www.davidrumsey.com/luna/servlet/detail/RUMSEY~8~1~3...

[rckoepke]

The ones I'm thinking of were "nomograms" (thanks to user 'chemeng'). Visually they look like perhaps a very specific subset of "Parallel coordinate" graphs. Definitely more for calculation rather than visualization. Evidently they were popular from around 1890 to at least 1950.

[kortex]

They are still quite useful for predicting boiling points under reduced pressure.

https://www.sigmaaldrich.com/chemistry/solvents/learning-cen...