Are double and triple contractions actually grammatically correct?

The major was a little man with upturned mustaches. he had been in the war in libya and wore two wound-stripes. he said that if the thing went well he would see that i was decorated. i said i hoped it would go well but that he was too kind. i asked him if there was a big dugout where the drivers could stay and he sent a soldier to show me. i went with him and found the dugout, which was very good. the drivers were with it and i left them there. what effect does hemingway’s limited use of adjectives have? it slows down the narration by interrupting the action. it makes the few descriptive words he does use more vivid and forceful. it makes the narrator seem powerless and insincere. it prevents the readers from filling in the details with their own experiences.