Sentence:  ... I chanced once, when I called during the day, to meet at the rehearsal M'lle Clarisse, the <WSD>aerialist</WSD> ... I looked at her carefully, and I could not divest myself of the impression that she was, in spite of her compact and strongly built little frame, much too delicate and fragile a person to go flying through the air from trapeze to trapeze. 
Meaning of the word marked with <WSD> tags:  An acrobat performing high off the ground, defying a fall to earth, as on a trapeze or a tightrope.