Note 1 — Chapter V
Reading edition
The workings of the Time-telespectroscope involve all the intricate postulates and mathematical formulae of Time-traveling itself. As a matter of practicality, however, the results obtained are simple of understanding. The etheric vibratory rate of the vehicles while traveling through Time was constantly changing. Through the telespectroscope one cage was visible to the other across the five hundred feet of intervening Space when they approached a simultaneous Time; when they, so to speak, were tuned in unison.
Thus, Harl explained, the other cage would show as a ghost, the faintest of wraiths, over a Time-distance of some five or ten years. And the closer in Time they approached it, the more solid it would appear.