This is actually a "fix-up" - with Chapters 1 to 5 rewritten and condensed from the story of the same title in All-Story Weekly June 22, 1918. The rest of the book (Chapters 6 to 35) had origins as "Conquest of the Moon Pool" - a six part serial in All-Story Weekly, beginning February 15, 1919. (I haven't seen a copy of that original to compare the texts - so I can't say how revised the book version is...)