Sentence:  But true it is, that when the oil is spent / The light goes out, and <WSD>wick</WSD> is thrown away. 
Meaning of the word marked with <WSD> tags:  A bundle, twist, braid, or woven strip of cord, fabric, fibre/fiber, or other porous material in a candle, oil lamp, kerosene heater, or the like, that draws up liquid fuel, such as melted tallow, wax, or the oil, delivering it to the base of the flame for conversion to gases and burning; any other length of material burned for illumination in small successive portions.