Keen Detective Funnies #20

Dean Denton, the scientific detective, finds himself aboard the British liner Royal Crown bound for New York when magnetic mines—a deadly new wartime weapon—begin appearing in the surrounding waters. When a nearby ship is destroyed by the mines, Dean teams with the ship's radio operator Hall to devise a bold countermeasure using Hall's cyclotron to magnetize the vessel's hull and repel the deadly explosives. As Dean guides the ship through the minefield to rescue survivors, he uncovers something even more sinister lurking in these waters.

Robert Churchill, an English detective and gun expert, demonstrates how firearms leave distinctive marks on bullets—the "fingerprints" that can link a weapon to a crime. Using his innovative "Silent Detective," a double microscope that compares test-fired and crime-scene bullets side by side, Churchill reveals how these friction marks become crucial evidence in solving murders.