Tek 465b Analog Oscilloscope. Notice precision b-delay control high and to the right of the display.
The Tektronix 465b was the industry standard in 100MHz portable oscilloscopes for many years.
A dual timebase allowed it to examine related signals at different temporal resolutions.
A precision potentiometer could control the the delay before the second sweep allowing precise time measurements between widely separated events.
Demonstration
This short video shows an example of how you would use the delayed timebase on an oscilloscope. This example uses a similar Tektronix 485 oscilloscope and bursted sinewave signal from a function generator.
YOUTUBE J-7MycqHPOs Using the delayed timebase
For more videos visit the Vintage Tek Museum feature on using an analog scope. webpage 