Sentence:  But then I had the [massive] flintlock by me for protection. ¶...The linen-press and a chest on the top of it formed, however, a very good gun-carriage; and, thus mounted, aim could be taken out of the window at the old mare feeding in the meadow below by the <WSD>brook</WSD>,nb.... 
Meaning of the word marked with <WSD> tags:  A body of running water smaller than a river; a small stream.