Original oil and gas trade magazine vintage ad for LEONARD REFINERIES INC. Shown in photograph are Mr Clayton Weaver and Mr Forrest Holcomb, superintendent and cracking plant operator, discussing the function of air supply in catalytic cracking and how the Cooper-Bessemer centrifugal compressor supplies big-volume air around the clock. Refinery located in Alma, MI. This unique 1959 old petroleum refining industry magazine advertisement would display beautifully matted and framed. Two page gatefold advertisement.