Although the story is not about time travel, the characters do spend the first couple of
pages reminiscing about their disappointing experiences with a time machine.
— Fred Galvin
“And watching the great Pythagorous at work.” “And the three days that he
spent on that little surveying problem. How one longed to hand him a slide-rule through
the barrier and explain its working.”
From an unspecified location, circa 1960 ⋙ to observe various times and places in the past at an unknown time. Multiple round trips. Note: The trips are all part of a discussion of the gang’s past adventures using the Recapitulation Correlator, aka the Time Machine.