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.
To prevent mildew on canvas, soak it in bluestone water, or if the mildew is already present, coat the parts well with ordinary soap and rub on powdered chalk, or whiting. A solution of corrosive sublimate, well weakened with water, will also prevent mildew, but owing to its poisonous nature it is best to use the former method. - Contributed by A. Ashmund Kelly, Malvern, Pa.
When the steel point of a compass is lost, a phonograph needle makes a good substitute.