What precautions did Captain Smollett take against mutiny?

From the text:

Very good," said the captain. "Then, as you've heard me very patiently, saying things that I could not prove, hear me a few words more. They are putting the powder and the arms in the fore hold. Now, you have a good place under the cabin; why not put them there?—first point. Then, you are bringing four of your own people with you, and they tell me some of them are to be berthed forward. Why not give them the berths here beside the cabin?—second point."

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"Well, gentlemen," continued the captain, "I don't know who has this map; but I make it a point, it shall be kept secret even from me and Mr. Arrow. Otherwise I would ask you to let me resign."

"I see," said the doctor. "You wish us to keep this matter dark and to make a garrison of the stern part of the ship, manned with my friend's own people, and provided with all the arms and powder on board. In other words, you fear a mutiny."