The passage is:
"I also now first saw the use of the quadrant. I had often with astonishment seen the mariners make observations with it, and I could not think what it meant. They at last took notice of my surprise; and one of them, willing to increase it, as well as to gratify my curiosity, made me one day look through it. The clouds appeared to me to be land, which disappeared as they passed along. This heightened my wonder: and I was now more persuaded than ever that I was in another world, and that every thing about me was magic."