Sentence:  Was it so irreconcilable, Warwick wondered, as still to peal out the curfew bell, which at nine o'clock at night had clamorously warned all negroes, slave or free, that it was unlawful for them to be abroad after that hour, under <WSD>penalty</WSD> of imprisonment or whipping? 
Meaning of the word marked with <WSD> tags:  A punishment for violating rules of procedure.