The Melrose Park, Illinois, Dur-O-Lite pencil is Bakelite, celluloid marble, and chrome-trimmed metal. Twist the black end to advance the 1.1mm lead. Pull off the cap for the eraser, which has a clever notch for assisting in the removal of the old eraser in its metal holder, and inserting a new one. It is one of the reasons Dur-O-Lites are interesting--many models have some clever design and engineering features. The pencil has a streamlined 30s feel to it, combined with the materials of the 1930s and the pre-1938 lead size. It is 5 & 3/8 inches.
The tip pulls away to show the Dur-O-Lite trademark and the sturdy screw-mechanism with paddle end that advances the lead. The top of the trade-marked nose that the tip fits over cleverly becomes a decorative bead on the barrel of the pencil. Someone thought that through effectively!
The Waterman-Waterbury Company was a maker of patented "heating systems" for school houses all over the Midwest and beyond. Here is one of the early "systems," a cast iron wood or coal burning stove encased in a decorated housing that drew cold air from an outside air intake, heated it in the housing around the stove, and allowed it to rise from the top of the housing as warm air by natural convection. Their claim was that this provided better ventilation and cleaner warm air.
Here is the heating system as it looked in a 1919 school room.