To verify the laws of triangle, parallelogram and polygon of forces. Heavy aluminium casted top disc, 40 cm. diameter is accurately turned and graduated in degrees. It is provided with 4 frictionless adjustable pulleys having pivots of hardened steel, cords from central ring carries hangers for slotted weights. Pulley clamps have an index to show direction of forces. The base is of heavy cast iron with levelling screws and vertical rod is nicely polished supplied complete with 4 mass hangers and 12 masses (2 x 10 g, 2 x 20 g, 4 x 50 g, 4 x 100 gm).
