Sentence:  The departure was not unduly prolonged....Within the door Mrs. Spoker hastily imparted to Mrs. Love a few final sentiments on the subject of Divine Intention in the disposition of buckets; farewells and last commiserations; a <WSD>deep</WSD>, guttural instigation to the horse; and the wheels of the waggonette crunched heavily away into obscurity. 
Meaning of the word marked with <WSD> tags:  Low in pitch.