Under the Ocean to the South Pole; or, The Strange Cruise of the Submarine Wonder, by Roy Rockwood. New York: Cupples & Leon, 1907.
Roy Rockwood was a house pseudonym for the Stratemeyer Syndicate. According to this site (as well as wikipedia), Under the Sea was penned by the prolific Howard Garis.
This is the last of the pre-1923 Roy Rockwood Great Marvel series at Project Gutenberg. Nothing like completing a set!
Thanks to Emmy for post-processing this book.