Another really cool thing is to have the sextant, it's like having a walking teleporter. In the 2nd level when you reach a room where you find a piece of the scroll (I can't remember which part either) there are two pillars in the bottom right corner, chop through these and you'll hit a switch that activates a secret door. Walk through the door and there's your sextant!!!

Note: The only other clue I can give you is that it's below the room where you have to lure the goblin to step on the switch.