They made big spots and patches of light all about the room.

I could not shut my eyes for watching them, for they were not all the same shape, and they kept changing and moving; at last they got so faint, I was afraid the Rushlight was going out, so I jumped up and went to see, and I found there was a very big thief in the candle, so I got the snuffers out of my candlestick, and snuffed it, and got into bed again; and now there were beautiful big moons of light all over Margery's bed-valance.
Thinking of the thief in the Rushlight made me think of a thief in a castle, and then of thieves getting into our house, and that if one got in at my window I could do nothing except scream for help, because Grandmamma keeps the Watchman's Rattle under her own pillow, and locks her bedroom door.

And then I looked at my window, and saw a bit of light, and it made me quite cold, for I thought it was a burglar's lantern, till I saw it was the moon.
Then I knew how silly I was, and I determined that I would not be such a coward.

I determined I would not think of burglars, nor ghosts, nor even Margery.
Margery and I are quite sure that we can think of things, and prevent ourselves thinking of things, by trying very hard.

But it is rather difficult.
I tried, and I did.