Project Gutenberg 2016-10-05 Public domain in the USA. 164 Powell, Van Powell, Ardon Van Buren The Mystery of the Fifteen Sounds The Mystery of the 15 Sounds Produced by Stephen Hutcheson, Dave Morgan and the Online Distributed Proofreading Team at http://www.pgdp.net "The Mystery of the Fifteen Sounds" by Van Powell is a children's adventure novel written in the late 1930s. The story centers on young Roger Brown, who aspires to be a "Modern Pioneer," inspired by his father’s expedition to Borneo. Throughout the novel, Roger collaborates with his cousin Grover, who runs a scientific research laboratory, to solve complex mysteries involving scientific principles, including the disappearance of dangerous inoculated rats and the mysterious "Voice of Doom." The opening of the story establishes a sense of urgency as Roger discovers that alarms have gone off in his cousin’s laboratory. He insists to Grover that something is awry, especially with the sudden quiet of the alarms. As they investigate, they find that the laboratory's white rats, carrying dangerous pathogens, have vanished. The plot unfolds with hints of mystery, danger, and adventure as Roger and Grover confront challenges that combine both science and intrigue, leading them into various thrilling scenarios while trying to uncover the truth behind the strange occurrences in the lab. (This is an automatically generated summary.) Reading ease score: 81.6 (6th grade). Easy to read. en Detective and mystery stories Laboratories -- Juvenile fiction PZ Text Browsing: Children & Young Adult Reading Browsing: Crime/Mystery Browsing: Literature Category: Children & Young Adult Reading Category: Crime, Thrillers and Mystery Category: Adventure 412690 2025-06-21T08:55:45.492715 text/html 401469 2024-10-23T01:12:29 text/html 543424 2025-06-21T08:55:54.810632 application/epub+zip 559030 2025-06-21T08:55:47.920658 application/epub+zip 236194 2025-06-21T08:55:46.744690 application/epub+zip 713171 2025-06-21T08:55:59.858631 application/x-mobipocket-ebook 658915 2025-06-21T08:55:53.625625 application/x-mobipocket-ebook 336645 2022-09-24T06:37:18.532827 application/x-mobipocket-ebook 365191 2023-09-23T05:27:39.656844 text/plain 345343 2024-10-23T01:12:29 text/plain; charset=us-ascii 15615 2025-06-21T08:56:00.027581 application/rdf+xml 31435 2025-06-21T08:55:46.873666 image/jpeg 4966 2025-06-21T08:55:46.809668 image/jpeg 511963 2025-06-21T08:55:45.539718 application/octet-stream application/zip Archives containing the RDF files for *all* our books can be downloaded at https://book.klll.cc/wiki/Gutenberg:Feeds#The_Complete_Project_Gutenberg_Catalog en.wikipedia