6.2 - Pictorial Evolution Of Measurement Instruments
Left- the Crooks tube invented in 1870 by the Bristish physicist William Crook for detecting electrons particles.
Right: a type of cathode ray tube.
Early valve tester made circa 1924
Inductance, resistance and capacitância bridge manufactured Tchécoslovaquie in the in 1930 . The first commercial oscilloscope introduced by Allen B. DuMont Labs. in 1930. Deflection connections were made directly to the Cathode Ray Tube. The box shown acting only as a high-voltage power supply.