In the time in which Dickinson wrote, caskets would be placed on wooden planks and suspended over an open grave during a funeral. The planks would be removed and the casket would be manually lowered by six people when it came time for interment. In this metaphor, the speaker replaces these planks with “reason.” This suggests that her mind is in the casket suspended over a grave and held up only by these thin planks of reason.
"Then Space—began to toll,..."See in text(Text of the Poem)
In Christian and Catholic funeral traditions, a bell would be rung slowly to signal someone’s death and passage into the next life. The word “toll” alludes to John Donne’s poem “For whom the Bell Tolls,” a poem in which the speaker hears church bells ringing at a funeral and recognizes his own inevitable death.
