In this issue

• Vacuum Tubes Used in the First Trans-Atlantic Flight
• High-Voltage Processing of Big PowerTubes
• The Eimac View:
Conditioning of Large Radio-Frequency Power Tubes
• Internal Control Symbols for RCA Tubes RCA (Dowd Archive)
• Quality Control of Vacuum Tubes Philco Electronic Supervisor
• The Catkin Tube Radio Engineering.
• Post Office Controlled Valves A. C. Farnell and Arthur Wolfenden
• TCA Awards The Rules