The Time-Techs of Kra

The elusive technical knowledge of eons, past and future, was held captive by the mighty Kralons—learned giant insects that seined the stream of Time for the great Truth that would mold them into unrivalled masters of the universe.
The little gray man peered timidly over gold-rimmed spectacles at the great black hole which yawned hungrily almost at his feet. He edged back cautiously from the massive steel lattice which guarded its circumference, then plucked timidly at the sleeve of the blue-uniformed guard who stood impressively erect before the barrier's huge gate.
I—I beg your pardon. Could you tell me when the next one leaves? he asked in a voice as colorless as his thin, nondescript features.
The guard catalogued the speaker with a glance, and a superior smile lifted the corners of his lips.
Not figuring on making the Big Drop, are you, Uncle? he asked in obvious amusement.
Well, I—
Then the gilt epaulets on the guard's padded shoulders jerked as he came suddenly to a respectful attention.
Next Diamvator leaves promptly at 2:30 P.M., sir. Arrives at the Antipodes at 6:30 P.M. Central Standard Time, sir.
The obsequious reply brought a veil of mild surprise to the little man's pale gray eyes.
Then it was replaced with a twinkle of understanding as he saw the Terminal Agent approaching.
J. B. Andrews, the big bluff Supervisory Agent of Earth-Tube, Incorporated, cast a cursory glance at the little gray man, then turned to the guard.
The 'Vator will leave at 2:35 P.M. today, Jamieson. Five minutes later than schedule. You will act accordingly.