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.
Procure a few pieces of cotton string, each about 1 1/2ft. long, and fill them well with soap. Prepare a brine by dissolving three tablespoonfuls of salt in a cup of water. Place the strings in the brine and allow them to soak for two hours, or longer. It is necessary that they be thoroughly saturated with the brine.
When taken out of the brine and thoroughly dried, suspend one of them from a nail on a ledge, and hang a finger ring on its lower end. Apply a lighted match to the string and allow it to burn. The ring will not fall, but will hang by the ash. - Contributed by C. Frank Carber, Dorchester, Mass.