In regards to Dickinson's poem "He ate and drank the precious words", special circumstances are needed to evoke delight.
What Dickinson is illustrating in the poem is that one must look to objects, concrete things, in order to find delight. The speaker is illustrating the fact that a man, facing an uncontrollable history, looks to a book (presumably the Bible) in order to find hope.
Here, the special set of circumstances is the man's misfortunate past, he is poor and growing old ("his frame was dust"). In order to find peace with his life (delight), the man turns to the words of a book in order to give him hope and allow him to loosen his spirit.
Downtrodden by his lack of monetary wealth and his weakening body, the man looks to "precious words" in order to find the strength to go on.
Therefore, the man is looking to a specific place ("a special set of circumstances") in order to find delight in his life.