This model serves to indicate the humidity of the air. It consists of the house, turntable, and figures, the turntable being suspended on a violin string. The violin string absorbs moisture from the air and untwists, thus causing the man to come out; when the air become dry the string twists tighter, thus causing the woman to come out. The model should be placed outdoors but not exposed to rain or sun.
The arches of the doorways may be made with a big bit (1-3/8") or a scroll saw. If a bit is used, bore a hole for the spur first, lest it split the board. While boring hold the board vertically in the vise. The portion cut off between the doorways can be sawed with the tip of the back-saw if the board is laid flat on the bench-hook. The slanting lines at the top, also, can be sawed while held down on the bench-hook.
After the front, back and sides are made, nail the back to the sides, but screw the front. When this is done, put the house in the vise in an upright position and plane the tops of the sides slanting. Notice that one roof is wider than the other. Nail the narrower one first, with the grain running from front to back. Do not drive nails into the front but nail it securely at the back and side.
Letting the plane rest on the other side of the house, plane the upper edge of this roof slanting, so that the other roof will fit. Nail this in place; set all nails; and plane the upper edge of this roof slanting, letting the plane rest on the first roof. Two brads may now be driven near the center of the ridge-pole to hold the roofs together. After making the floor, place the house in position on it (1/4" from back, 1/2" from ends) and draw a line around the house. Remove the house; drive three brads straight down thru the floor; pull them out and start them from the underside in the same holes; then put the house in place again and drive the brads home. Put in more brads to hold the house securely.
To make the chimney, saw a notch 3/16" deep in the end of a 3/4" square stick. If it fits on the roof, bore a 5/16" hole thru its center, and saw the chimney off 3/4" long. Glue it 3/8" from the front end of the roof. When dry, bore the hole thru the roof. [Pg 60]The chimney top with the dowel attached to it below is made to revolve so that the Hygroscope may be adjusted. To make the chimney top, bore a 1/4" hole into the end of a 1/2" dowel; then saw it off 1/2" and glue in the upper dowel. Make the turntable somewhat round at each end. In the center of it, glue and nail the lower dowel. Next, paint the house if desired. The violin string is glued and wedged into holes in the upper and lower dowels so that the turntable will swing 3/16" above the floor.
The man and woman may be made of cardboard, wood, clay, chalk or plaster of Paris; or they can be bought at a toy store. Painted in bright colors and shellacked, or varnished, they look well. They can be made to balance on the turntable by adding a piece of lead. Of course, neither they nor the turntable should touch any part of the house as they swing around.