The captain asks Jim to "keep a weather eye" open for a one-legged seafaring man and to let him know immediately if he should see anyone like that. He says he'll pay Jim four pennies a month for this work.

A few things are striking about this arrangement. First, it's clear that the captain, himself a ferocious individual, is afraid of this one-legged man, although why this should be the case is uncertain. Second, in asking Jim to keep lookout, the captain is taking Jim into his confidence; while Jim perhaps would rather not have this job and there is a sense the captain is taking advantage of him, at the same time, there is a kind of vulnerability in the captain needing this service. In other words, it serves to humanize the captain a bit. Jim says that he "shared" the captain's alarms, meaning that any danger the captain feared was also something Jim (and his parents) should fear.

Third, of course, is the fact that the captain is not very good about paying Jim's wages. This is perhaps because of the captain's tendency to not settle his debts and to intimidate people into not even asking for their money; this is the case with Jim's father, for instance. Jim, however, does ask him for his money, and, while he is initially ignored, he does eventually get it, because his watchfulness is an important service to the captain.