Here's a breakdown of how the poem achieves this:
* Imagery: The poem uses vivid imagery of a "low," "ponderous" sky, suggesting a sense of weight and pressure. The "heaviness" of the air and the "frost" on the ground contribute to this feeling of impending doom.
* Simile: The comparison of the sky to a "sick" person further reinforces the sense of illness and decay. The "wind" and "birds" are also described as "dying," adding to the atmosphere of impending death.
* Tone: The poem's tone is somber and reflective. Dickinson uses short, simple sentences and repetitive phrases to emphasize the feeling of stillness and anticipation.
* Theme of Mortality: The poem explores the themes of mortality and the fragility of life. The imagery of death and decay suggests the inevitability of our own demise.
While the poem does not explicitly state what the reader should feel, the overall mood is one of unease and impending doom. It leaves the reader with a sense of foreboding and a questioning of the unknown future.