"Les enfants du Capitaine Grant" and "Vingt mille lieues sous les mers"

I got this AMAZING BOOKS! The smell of an old book in perfect shape is something special. It's the VI Jules Verne Hetzel edition and I started to learn french just to read them. Something its weird is that I don't know the printing year because it is not shown at any part of the book... If someone know in which year was the VI Hetzel edition.