Frank Reade Jr.'s Deep Sea Diver the "Tortoise;" or, The Search for a Sunken Island
From Author Wars - https://authorwars.com/books/frank-reade-jrs-deep-sea-diver-the-tortoise-or-the-search-for-a-sunken-island-2431231.html
From Author Wars - https://authorwars.com/books/frank-reade-jrs-deep-sea-diver-the-tortoise-or-the-search-for-a-sunken-island-2431231.html