No mere armchair adventurer, he did quite a lot of traveling, too.
Having home-schooled our daughter in the 80's, I can tell you that my available resources ran very thin back then, compared with what is available now. One does what one can with what one has.
Many of my poems require me to explore such things as airships,
medieval pirates, and the like. For my "Airship" poem, I watched Eye of the Storm, (http://vimeo.com/19659763), over and over.
I watched the videos of various multi-player crews playing Guns of Icarus, my favorite being: http://youtu.be/Og9XUbrpHY4. And I happily got to read Clockwork Twist, Waking, by Emily Thompson.
For this poem I also had fortunate access to the movie, The Three Musketeers (2011), which features a rather vivid airship. It was a delight, while watching this film to declare, "I'm doing research!"
The point of all of this was to get a personal perspective of what a real airship might feel like and look like. A writer generally knows something about a subject, and these were as close as I could get.
Without the internet, or film, my imagination would have carried the full load, which is usually quite fine, but the details I needed were a mystery to me, since I knew next to nothing about any sort of ship.
And, while I'm at it, I must admit that I really, really wanted to be on an airship. Thus this poem became an excuse to delve deeper into my research, and to find some way to, more than less, "be there."
I imagine that Mr Verne might have found himself a bit obsessed with the wish to be on Nemo's Nautilus. When one writes as thoroughly and visually as he did, I think that one could sense that.
So, whether it was through to his personal travels or his trips to the library, Jules Verne gleaned a wealth of information about his world. Just imagine if he had had access to today's internet, back then.