How does "The Monkey's Paw" create an atmosphere of horror?

The atmosphere of the story is entirely horror; there is a
brief scene of familial comfort and home life at the beginning, and then events move
forward steadily, without pausing, and descriptions become negatively representational
instead of neutral or positive. Mr. White:

readability="7">

...gaz[es] at the dying fire, and see[s] faces in
it. The last face was so horrible and so
simian...

These descriptions
at first are subtle; while the narrative seeks to show things as normal, the language
becomes more and more negative, with short sentences and sharp exclamations from the
characters.

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"I'm sorry--" began the
visitor.

"Is he hurt?" demanded the
mother.

The visitor bowed in
assent.

These language
choices, as well as the shortness of the narration, give the story a sense of
claustrophobia, that there is little room for the characters or even the reader to relax
and breathe. Simple descriptive language allows the final part to be the most
terrifying:

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There was another knock, and another. The old
woman with a sudden wrench broke free... He heard the chain rattle back and the bottom
bolt drawn slowly and stiffly from the socket. Then the old woman's voice, strained and
panting.
(Jacobs, "The Monkey's Paw,"
gaslight.mtroyal.ca)

Each
part adds to the sense of unease: the first part is warm, with fire imagery, the second
part is neutral, with both fire and death, and the third part is cold and harsh, with
guttering candles and dark passageways. These elements give the story a morbid
atmosphere, and the sense that normalcy in the universe has been
damaged.