Sentence:  “... <!-- quote in original --> Sidi, I was busy in the exercise of my functions, occupied in <WSD>brooming</WSD> the front of the stables, when who should come but Hhamed Ould Denéï on horseback, at full gallop, as if he were going to break his neck. ...” 
Meaning of the word marked with <WSD> tags:  To sweep with a broom.