This document rescued from the fire at the Sanctum Lodge, 13 Chapter, details an empirical experiment in time travel.
With this information you can send a subject back into time to see you enter the Sanctum Lodge and hold up a solitary playing card – this will be used as the test focus. The subject then returns to the current time with the proof of the reality of her visit.
A routine using guided visualization, psychological forcing with a good mechanical out.