Victorian books were often very small, soft-covered and portable. The original pocket books, for the pocket. I once read that Leslie Stephen sometimes walked 40 miles in a day, books in his pockets, reading while he walked. I had a grandfather who would walk out with gun, dog and book across the prairie from the last street in Calgary, 18A SW, where he lived. He was born in 1875, came to Canada in 1908 bringing with him his violin, his patent-leather dance slippers, his school blazer and his Hardy fishing rod. Things were different then.
Books were one's companions in one's solitary pursuits. Books of poetry were high on the list, perhaps because poems then often had a walking rhythm, were episodic, compressed, gave one lots to think about. Wilfred Owen took his Keats to the Front in WWI.
We resist, today, being left alone with our thoughts – there is certainly a lot of stuff that rushes into the void, sort of as if we don't have any thoughts of our own really. Maybe we don't, but if my head is an empty desert I would prefer it be filled with Yeats or Heaney or Hughes. personally. Unfortunately I hardly have the time to stroll about, book in hand.