Sentence:  "A fine man, that Dunwody, yonder," commented the young <WSD>captain</WSD>, as they parted, and as he turned to his prisoner. "We'll see him on in Washington some day. He is strengthening his forces now against Mr. Benton out there.nb...." 
Meaning of the word marked with <WSD> tags:  An army officer with a rank between the most senior grade of lieutenant and major.