This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
A good way to keep an inkwell of the type shown in the sketch clean is t o place a marble over the opening. The marble keeps out flies and dust, is easily rolled aside and is no obstacle to the pen entering the well. - Contributed by James M. Kane, Doylestown. Pennsylvania.