Chapter 4: Among The Islands. 

"Now, let us go through our calculations again," the captain said when they entered his cabin. 

"How long will you be, Captain?" the first mate asked. 

"Half an hour, Standing." 

"Then I will come again or, if you want me before that, send for me," and the first mate went out on deck again, for though well skilled to handle a ship in all weathers, and as brave and hardy a seaman as sailed out of Plymouth, James Standing could neither read nor write; and though in a rough sort of way he could reckon the course a ship should lie, and make allowance for leeway and currents and baffling winds, and could bring a ship into any port in England or the Low Countries, he was of no use in a matter of this kind. 

Pengarvan was a good scholar, and Reuben had taught him what he knew of navigation, and always made him keep a log from the time when he first became a mate; at first comparing their calculations every day, and then but once a week; arguing over the allowances each had made for tide and leeway; and sometimes finding to his surprise, on arriving in port, that Pengarvan's calculations were even nearer to the truth than his own. 

This was a great satisfaction to him, for he felt that, if aught should happen to himself when on a voyage, Pengarvan could be trusted to bring the Swan home, as safely and surely as he could himself. Roger had, for the last two years, been going through the same schooling; but as yet he was very far from attaining accuracy, being unwilling to make sufficient allowance for the great leeway that a vessel, in those days, made with the wind abeam. 
Who begins the dialogue in the cabin? Who is he talking to? What does the captain want to double-check? Does the first mate ask him the time something will take? How much time will elapse? Will it involve sitting? Does someone offer to return? Where did the first officer depart to? Was he an inept sailor? Was he courageous? Did he possess good endurance? What skills was he lacking? What was his name? Who had good scholastic ability? Did he know anything about navigating? Who had instructed him? What did he record? Did Reuben feel his work was inaccurate? How did he feel about this? What did he trust Pengarvan to do as well as he could?
the captain the first mate calculations Yes. Half an hour. No. Yes. out on deck No. Yes. Yes. He could neither read nor write. James Standing Pengarvan Yes. Reuben a log No. great satisfaction bring the Swan home