Meldes Vibrating String Apparatus, consists of a string and an oscillator to generate different frequencies, Requires 6 V, 50 Hz power source, with 4mm plug leads, Weight (lb): 1.4, Length (in):11.0, Width (in):6.0, Height (in):3.0
Spectrum Discharge Tube, Mercury Gas to show spectral lines of pure substances. Tubes approximately 260mm long, central capillary portion approximately 3-1/2 to 4 (90-100mm) long with electrodes sealed at both ends and connected to lead wires protected by metal caps