How to Make a Hygrometer
Simple Hygrometer
Mount a wire on a board which is used for a base and should be 3/8 by 4 by 8 in., as shown in the sketch. A piece of catgut—a string used on a violin will do—is suspended from the bent end of the wire. A hand or pointer is cut from a piece of tin and secured to the catgut string about 1/2 in. from the base. A small piece of wood and some glue will fasten the pointer to the string. The scale is marked on a piece of cardboard, which is fastened to the base and protected with a piece of glass.
Contributed by J. Thos. Rhamstine.