The tramp steamer Drake plowed away from the coast of India and pushed its blunt prow into the Arabian Sea, homeward bound.
-- Narrator (chapter 1 paragraph 1)

Importance: These first words of the novel introduce the novel's exotic setting, but also hint that the novel will progress elsewhere because there is traveling to be done before the Drake is home.

Alec forgot his problems in the beauty of the stallion as he swept along, graceful in his swift stride, his black mane and tail flying.
-- Narrator (chapter 3 paragraph 14)

Importance: Alec can stop to appreciate the Black's beauty in a manner that removes his thoughts from his own problems. The transcendent quality of the animal becomes more and more apparent as the novel progresses.

Painted on the gray board was the name DRAKE- it had been part of one of the lifeboats! Alec stood still a moment, then grimly he fixed the plank securely in place.
-- Narrator (chapter 3 paragraph 16)

Importance: This is the defining moment...