In the last quarter of the 19th century, William Crooks discovered the visual effect cathode rays have inside a vacuum tube. In , J. Thompson discovered the cathode ray through his experiments but due to the extremely high voltages required, these early findings were restricted to the laboratory. In the 's Western Electric developed a cathode-ray tube CRT that ran on relatively low voltages compared to these earlier experiments. This opened the door for the manufacturing of bench and portable oscilloscopes for laboratory or service use and eventually television.
The following shows part of my collection. This scope was being thrown out at Caltech, and I rescued it. I downloaded the manual from BAMA. It is available here. Amazingly I subsequently found at Caltech in an old filing cabinet the original manual that came with this This is nice to have. I also found the original scope cart, model , complete with instructions, that was purchased at the same time.