GPS

"Time Patrol."

"Everard swung onto the time hopper, set the controls for A.D. 464 at Addleton Barrow, a summer midnight, and threw the switch." (4, p. 30)

There are four pieces of information there -

year: 464 AD;

season: summer;

time of day: 12:00 am;

place: Addleton Barrow.

Does Everard let the timecycle choose which day of summer in 464? How does he tell it to go to Addleton Barrow? That is easier for us to understand now than in 1954. The computer in milieu HQ, where Everard is, will have identified the Barrow with a very precise set of spatial coordinates.

The transition is instant for the two Patrolmen:

"There was a full moon." (5, p. 30)

Also, there is a dark forest and a wolf howls. They have just come from London, 1894, but they retain the advantages of technology:

"Rising on the antigravity unit, they peered across a dense, shadowy wood." (ibid.)

By adding antigravity to time travel, the Time Patrol has achieved the Time Traveller's:

"'...vague inkling of a machine -

"'That shall travel indifferently in any direction of Space or Time, as the driver determines.'"

-HG Wells, The Time Machine (London, 1973), 1, p. 11.