The IEC 'Melde's Apparatus' is a new item that was earlier known as the 'Vibrator'. It is used to vibrate a length of cord horizontally (maybe 1 to 2m length) as it is pulled taut along the surface of a bench and passed over the edge of a table with a weight attached to create a known tension in the cord. The armature (the moving part) of the vibration device has a hole in the tip for the attachment of the cord. The kit includes a bench clamp and a pulley on rod to guide the cord over the bench edge and to be adjusted so that the cord is parallel to the bench top. When a high power Signal Generator is connected to the Melde's Apparatus, the armature is adjusted and clamped to vibrate at this known frequency. The cord it attached and tensions to provide excellent patterns that are measured and studied regarding frequency and wavelength.