The speaker looks back at a past that was once wild and full of life, and finds that memory isn't enough to get through the present. The title, "Touchstoner," seems to play on "touchstone," an object used to test quality, but also hints at stone, which fits the odd image of being "dug out" of a moment, as if the speaker were a find pulled from the earth.
That moment is called "a poor candle," a weak and flickering light for walking through darkness. The speaker seems to be moving through "the city where we danced / beyond all moderation," a place that holds a shared, joyful excess. The word "we" suggests someone else was there, and the poem's tone hints at loss, though it never says what happened.
The mood is quiet and wistful. There is longing for that intensity, but also honesty: the speaker won't pretend that remembering a bright time can fully light the way now. The brief lines leave the darkness feeling large.