Future World Comics #2

In "The Secret Message!" from Future World Comics #2 (1946), Mel Mason, assistant to chief engineer James Cook at Borden Electronics, races to perfect the revolutionary Borden Device—designed to send full-color images by wire—while juggling urgent calls from the Belmar lab. But amid the hum of machinery and the pressure of progress, Mel finds himself entangled in a mystery at the Lamar plant that’s far more personal than any circuit diagram.

Mr. Mason walks his younger brother Charlie through the technical marvel of pulse-time modulation radio, demonstrating how a single carrier wave can transmit twenty-four separate messages simultaneously using a rotating electron beam and clever timing. As Charlie marvels at the cyclophone receiver and the transmitter tube that make it all possible, Mr. Mason reveals how he used this same technology to hide a secret message in plain sight—embedding it among twenty-three fake messages designed to confound anyone listening in, including the villain Supersonic. The story culminates with a live demonstration that proves the system works, leaving Charlie astounded by the ingenuity of modern radio engineering.

Jack Boyd's modified sonar technology becomes the key to a sunken fortune when his old friend Dan Deeping arrives desperate for work—his father's yacht, carrying a fortune in cash, went down years ago, and Jack knows exactly where and why. As the two prepare a salvage expedition aboard the yacht the Silver Streak, they find themselves racing against dangerous rivals who'll stop at nothing to reach the wreck first and claim what's waiting in the deep.

A character aboard the Silver Streak learns how sonar technology works—the same system that located the wreck of the Aires—as an expert walks through the echo-based principles using instruction diagrams and practical calculations. From the supersonic signals bouncing off the ocean floor to the mechanical receiver that converts vibrations into readable measurements, this three-page feature breaks down the fascinating machinery behind underwater detection in clear, hands-on terms.

Young Sparks Rogers combines his twin passions for radio and railroading when he discovers a gang of thieves planning to derail his friend Scorcher's locomotive—and a fortune in cash—along the tracks outside town. Racing against the clock to warn the train, Sparks must outwit the robbers and use his wits (and a bit of judo) to get word through before disaster strikes. A thrilling race between a quick-thinking kid and criminals who'll stop at nothing to claim their prize.

Sparks Rogers visits the CB-Q Radio Lab to learn about inductive radio from Dr. Boyle, who demonstrates how carrier current radio transmits voices over telegraph wires using frequency modulation. Through live demonstrations with an oscilloscope and a working connection to Locomotive 309, Sparks discovers how the system picks up and transmits messages between the wayside wires and the train's receiving coil.