“After I see that all our apparatus is fixed for the night.”
“You go ahead,” Potts grinned fondly at his chum, all suspicions forgiven, “I’ll see that everything er—uh—coagulates!”
THE END
The Mystery
of the
15 Sounds
By
Van Powell
When Roger’s uncle offered him an opportunity to help in his scientific laboratory while the boy’s parents were in Europe, Roger jumped at the chance. His uncle’s laboratory—one of the most perfectly equipped—was the most fascinating place in the world.
Even the latest scientific devices, however, could not keep out the “Voice of Doom” which sounded hollowly through the laboratories in the dead of night, or prevent the ghostly antics of the phantom kangaroo and his ape-like companion. These and many other occurrences make THE MYSTERY OF THE 15 SOUNDS one of the best boys’ mystery stories of the year.
Books for Boys
In selecting the books of this series we, as publishers, have tried to present a varied assortment, which will stir the imaginations of all boys. At the same time we have kept these stories from being nerve-wreckers.
Herman M. Appel Secret of the Flambeau, The. William Dixon Bell Sacred Scimiter, The. Moon Colony, The. Secret of Tibet, The. Walter Butts, Jr. Brothers of the Senecas. Graham M. Dean Agent Nine and the Jewel Mystery. Agent Nine Solves His First Case. Circle 4 Patrol. Daring Wings. Herb Kent, West Point Cadet. Herb Kent, West Point Full Back. Slim Evans and His Horse “Lightning.” Treasure Hunt of the S-18. Edwin Green Air Monster. Secret Flight. William Heyliger Big Leaguer. Detectives, Inc. Fighting Blood. Loser’s End, The. Norton H. Jonathan Dan Hyland, Police Reporter. Gilbert A. Lathrop Whispering Rails. Mystery Rides the Rails. George Morse Circus Dan. Extra. Vanishing Liner. John A. Moroso Nobody’s Buddy. Ambrose Newcomb Eagles of the Sky. Flying the Coast Sky Ways. Sky Detectives. Trackers of the Fog Pack. Van Powell Mystery of the 15 Sounds. Warren F. Robinson “G” Man’s Son, The. “G” Man’s Son, at Porpoise Island. Phantom Whale, The. Lieut. Noel Sainsbury Bill Bolton and the Flying Fish. Bill Bolton, Flying Midshipman. Bill Bolton and Hidden Danger. Bill Bolton and Winged Cartwheels. Harold M. Sherman Captain of the Eleven. Down the Ice. Interference. In Wrong Right. It’s A Pass. Over the Line. Strike Him Out. Tahara, Among African Tribes. Tahara, Boy King of the Desert. Tahara, Boy Mystic of India. Tahara, in the Land of Yucatan. Under the Basket. Wayne Whipple Young Abraham Lincoln. Young Franklin Roosevelt.