Sentence:  I had occasion […] to make a somewhat long business trip to Chicago, and on my return […] I found Farrar awaiting me in the railway station. He smiled his wonted fraction by way of greeting, […], and <WSD>finally</WSD> leading me to his buggy, turned and drove out of town. 
Meaning of the word marked with <WSD> tags:  To finish (with); lastly (in the present).