Captain Marvel Adventures #16

Captain Marvel discovers an ancient pre-Arabic trumpet with mysterious inscriptions and must say the magic word "Shazam" to transform into his superhero form. He teams up with Steamboat to stop a plot involving dynamite and a hypnotist villain who attempts to use mind control. After a fierce battle on a steamboat where Captain Marvel wrestles with the villain and fights off dynamite explosions, he ultimately defeats the criminals and saves the day by compressing the bomb fragments back to their harmless original size.