Joining his regiment in Barbadoes, he served there and later in Jamaica. There is a story told of him at this time which shows that the courage of the boy who had been the hero of a hundred daring escapades was his distinguishing mark in young manhood. A captain in the 49th, who was a crack shot, was the bully of the mess. Brock, who treated him with indifference, was singled out as a mark for his insult and was involved in a duel. The braggart was a little man, but Brock was six feet two—not a difficult target. Brock had the right, as he had been challenged, to name the conditions of the duel. When the party reached the grounds where the duel was to take place, Brock drew out his handkerchief and insisted that he and his opponent should fight their duel across it. This would minimize the disadvantage of his own great height. The bully, recognizing that for once he was fighting with equal chance to kill or be killed, refused the condition and fled. His brother officers declared that Brock had won a moral if not an actual victory, and they and he compelled the expulsion of the bully from the regiment. Shortly after this incident the 49th moved to Jamaica. Though he enjoyed the more eventful life there, Brock was a product of a hardier clime and could not stand the enervating air of the tropics. He fell a victim to fever and indeed nearly died of it. His man, Dobson, tended and restored him, and Brock, big-hearted and kindly then as later, never forgot what he owed to his trusty servant. Dobson remained with him till his death, which took place a short time before Brock set out on the expedition against Detroit. In 1793 Brock returned to England on sick leave and re-visited his old home, there to regain his health and strength. Subsequently, until the return of his regiment from Jamaica, he was engaged in the recruiting service. While employed in this most important work he kept up his hours of study, fitting himself for the greater things to come. In 1795, he purchased his majority, and in 1797, at the age of twenty-eight and after only twelve years service, was gazetted lieutenant-colonel of his regiment, soon afterwards becoming the senior officer. As commander of the 49th he had no easy position. The _morale_ of his men on their return from abroad was bad. The former commander was a poor disciplinarian, and his men had been allowed to get out of hand.