We got our hands on a stash of mid century scientific diagrams from the archives of the Griffith Observatory, Los Angeles. Figure 1, pictured here, breaks down "Principal Reactions in the Claus Process." Don't ask us to explain what on earth that means (something to do with recovering elemental sulfur from gaseous hydrogen sulfide?...), but we sure think it's a neat vintage print.
Newly mounted in a custom acid-free overlay window mat and protective plastic sleeve. The print is c. 1960s vintage; it's in very good/excellent condition.