II. Teaching Devices 1. Blackboard equipment. 2. Textbooks. 3. Rotary, toggle, and push switches; single pole, double pole, 3-way, 4-way, and electrolier switches. 4. Scrap wire. 5. Lamp socket and lamp. 6. Extension cord and source ofanbsp;...
|Author||:||United States. Office of Education, M. R. Bass, H. N. Peterson, O. W. Timpte|