TEACHING APPARATUS. 1031 



Mechanics. 



Black Rail to suspend the models from the school board. 



Lever for suspension. 



Lever supported on a fulcrum. 



Intermittent Motion, model to explain. 



Lock and Key, large working model of. 



Compound Wheel and Axle. 



Tilt Hammer. 



Screw, model to explain the action of. 



Train of Wheels, transmission of motion. 



Inclined Plane and Roller. 

 Sets of Pulleys : 



Four simple pulleys. 



Pair of long three-sheave pulleys. 



Pair of square three-sheave pulleys. 



Pair of White's concentric pulleys. 

 Centre of Gravity : 



Irregular board to explain centre of gravity. 



Leaning tower to explain centre of gravity. 



Parallelepipeds, a pair of, to explain centre of gravity. 



Double cone running uphill, to explain centre of gravity. 



Bowl-about, a toy to explain centre of gravity. 



Equilibrist, a toy to explain centre of gravity. 



Apparatus to explain Inertia. 



Plumb-line and Mercury Mirror. 



Pendulums made of various substances. 



Model of a Vernier. 



Whirling Table of iron, with set of adjuncts, to explain the action of 

 Centrifugal Force. 



Centrifugal Railway, model of. 



Gyroscope for explaining Inertia. 



Wedge, model, explaining action of. 



Percussion Machine for experiments on the collision of elastic bodies. 

 Constructive Mechanics : 



Tenon and Mortice. 



Scarfing. 



Half Lapping, 



Dove-tailing. 



Frictional Electricity. 



School Electrical Machine with 18-inch glass plate. 



Small, Cheap, Cylinder Electrical Machine. 



Conical Conductors to show accumulation of electricity near the point. 



Cylindrical Conductors to exhibit and explain induction. 



Set of three small and simple Conductors, Ball Cylinder and Cone, for 

 Elementary Schools. 



Ley den Jar with movable coats to exhibit the separation of the positive 

 and negative electricity. 1. The glass jar. 2. The inner coat. 3. The outer 

 coat. 



Unit Leyden Jar to measure strength of a charge. 



Set of Leyden Jars for obtaining powerful effects. 



Biofs Ball and insulated covers to show that the electricity is only on 

 the surface. 



Roll of Tin Foil to show effect of increasing surface. 



Insulated Stool on which to place a boy as a conductor. 



