My son has been reading Verne’s In Search of the Castaways (Captain Grant’s Children, Les Enfants du Capitaine Grant) on his Kindle, one of the favorite books from my childhood (I read it in Polish translation). He was resting at the gym and forgot his Kindle, so I loaded up a version from Project Gutenberg, and to his puzzlement he found it had material that the version he had on his Kindle—also from Gutenberg—was missing. So he had me investigate which version was more faithful to the French. Turns out both versions were abridged, but differently so.
According to Wikipedia, in 1876, Routledge produced what sounded like a three volume unabridged version, but it seems difficult to find a copy of it, unless one is willing to pay $50 per volume.
Finally, our library catalog turned up pdfs of volumes 2 and 3 on Hathitrust. (Annoyingly, to download volume 2, I had to login as part of a member institution, even though the catalog explicitly marks it as public domain.) After getting volumes 2 and 3 on Hathitrust, I had some more ideas what to look for in Google Books and found volumes 1 and 2 there.
For any other Verne fans, here are the links to the three volumes of the Routledge edition, all in one place:
I don't know for sure that these are unabridged, but the beginning of my son's test chapter (XVII of Volume 1) seems to have material from both of the abridged versions (one published by Lippincott in 1874 and one edited by Horne n.d.). Sadly, the three Routledge volumes do not say who the translator is, so I can't give credit to someone who deserves it (textually, it looks like the 1876 Routledge edition was the basis for the Horne abridged version).
