This ad from back cover of WORLD’S FINEST COMICS (1941) #7 was published two weeks after the eighth Fleischer Studios Superman short. The ad is notable not only for being the first full-page ad to promote the cartoons, but also because it is the first to list titles of individual cartoons. Only “Electric Earthquake” and “Volcano” had been released at the time of the ad’s publication. (No short titled “Twin Trouble” was released. It is unknown to me what that title was referencing.) The Superman image in the ad is from the Fred Ray-drawn cover to ACTION COMICS (1938) #52.