How does C.S. Forester use imagery in Hornblower and the Atropos?

Imagery:

"At Brentford, in the early light of the winter's morning, it was cold and damp and gloomy. Little Horatio whimpered ceaselessly..."

The furniture about him was what the ship's carpenter had made for him—canvas chairs, a rough-and-ready table, a cot whose frame was strung with cordage to support a coarse canvas mattress stuffed with straw. A canvas pillow, straw-filled, to support his head; coarse navy blankets to cover his skinny body. There was no carpet on the deck under his feet; the light came from a winging and odorous ship's lantern. A shelf with a hole in it supported a tin washbasin; on the bulkhead above it hung the scrap of polished-steel mirror from Hornblower's meager canvas dressing-roll. The most substantial articles present were the two sea-chests in the corners; apart from them a monk's cell could hardly have been more bare."