Today, in a coffeehouse or an airport, and other places as well, people work on laptops and netbooks. In 1895, you could buy a “pocket inkstand.” One in the Montgomery Ward & Co. mail-order catalog (republished in 1969 by Dover Publications) had a screw top and promised that it could not leak, which would certainly ruin your clothes.
The catalog suggests that this is good for tourists. I suppose you could write “picture postcards” and keep a travel journal, writing while sightseeing. Within ten years, the Brownie camera would change the way ordinary people recorded their vacations.
If you were in business or teaching, you could order a portable blackboard, even a cloth one you could roll up, stick in a bag, and use anywhere.