I'm afraid this is going to be on of those "I don't know what this is" wheels. I get what they're getting at. Let me try to explain. This chart automatically presents the wavelengths of the main absorption bands of 61 classes of chemical compounds. By setting the cursor to a given wavelength this chart automatically identifies most of those commonly occurring compounds producing absorption bands at that wavelength.
This wheel is 7 inches across and 8.5 inches high. The copyright date is 1965. The "Wavelength to Compound" side sports a shield of plastic on the disk.
I like the blurb about Barnes on the one side. "Our products are good." Well, you have ME convinced.
Don't fight it. Burn it!